V\,l 


MECJ-'ANICS    DEPT. 


ix\ 


1    20-10     1M 


SOLD  BY 

BOOK     DEPARTMENf"\ 


STEAM  POWER  PLANT 
PIPING  SYSTEMS 


THEIR    DESIGN,  INSTALLATION,  AND 
MAINTENANCE 


BY 


WILLIAM    L.  MORRIS,  M.E. 


NEW   YORK 

McGRAW-HILL   BOOK   COMPANY 
1909 


jejigineering 
Library 


;  i. 


MECHANICS 

COPYRIGHTED*  1909, 

BY  THE 

McGRAW   PUBLISHING   COMPANY 
NEW  YORK 


MY  MOST  ESTEEMED  FRIEND  AND  FORMER  ASSOCIATE 
J.  F.  RANDALL,  M.E. 

WHO  BY  HIS  TOLERANCE  ENABLED  ME 

TO  ENGAGE  IN 
POWER  STATION  DESIGN  AND  CONSTRUCTING. 


in 

735784 


PREFACE 


THIS  publication  treats  only  such  parts  of  the  power  plant 
system  as  are  directly  related  to  piping.  The  design  of  boilers 
and  engines  has  not  been  touched  upon,  but  their  operation  has 
been  covered.  All  auxiliary  apparatus  in  the  pipe  circuit  between 
the  boiler  and  the  engine  and  in  the  various  piping  systems  for 
steam,  oil,  air,  etc.,  have  been  treated  and  their  general  design 
discussed. 

It  was  not  the  intention  of  the  author  to  compile  existing 
information  and  make  a  handy  reference  book,  but  rather  to 
give  a  detailed  and  consecutive  treatment  of  the  entire  subject 
of  piping  as  applied  to  power  stations,  taking  up  the  design, 
installation,  and  operation. 

A  better  method  of  contracting  this  line  of  work  has  been 
fully  discussed,  one  which  will  entail  less  expense  both  to  the 
designer  and  to  the  contractor,  and  at  the  same  time  insure  a 
higher  grade  of  pipe  work. 

A  system  of  reasoning  and  analyzing  has  been  followed  that 
alone  in  itself  is  very  instructive. 

The  illustrations  are  all  made  from  original  sketches  prepared 
especially  for  this  work.  The  text  embodies  the  personal  expe- 
rience of  the  author  and  is  written  entirely  from  the  author's  own 
point  of  view;  therefore  it  is  very  probable  that  many  will  dis- 
agree with  the  methods  of  handling  certain  problems.  The 
author  will  be  grateful  to  all  who  disagree  with  him  if  they  will 
freely  offer  suggestions  and  criticism  which  may  be  used  in 
future  editions. 

W.  L.  M. 

CHICAGO,  ILL. 


CONTENTS 


CHAPTER    I. 

PAGE 

INTRODUCTION:  ORIGIN  OF  IMPROPER  PIPING i 

CHAPTER    II. 

PIPING  DIAGRAMS:  How  TO  LAY  OUT  SAME 7 

Fig.  i.  Diagram  of  Unit  System  Plant 10 

2.  Diagram  of  Six  Division  Plant u 

3.  Diagram  of  Loop  System  Plant 13 

4.  Diagram  of  Double  Main  System  Plant 13 

5.  Diagram  of  Systemless  Plant 14 

6.  Diagram  Elevation  of  Plant 16 

7.  Diagram  Study 17 

CHAPTER    III. 

PIPING   SYSTEMS:  EACH  SERVICE  SEPARATELY  CONSIDERED 20 

Fig.     8.  System:  Steam  and  Feed,  One  Division  Plant 21 

9.  System:  Fig.  8  Modified  to  Multiple  Division  Plant 22 

10.  System  (Sample):  Steam  and  Water,  3  to  4  Division  Plant  23 

11.  System  (Sample) :  Smoke  and  Air  Flues,  3  to  4  Division  Plant  26 

12.  System  (Sample):  Smoke  and  Air  Flues,  Modified  Form.  .  28 

13.  System:  Feed  Water  Meter,  Simple  Plan 34 

14.  System:  Feed  Water  Meter,  More  Flexible  Plan 35 

15.  System:  Fig.  14,  with  Meter  out  of  Service 35 

16.  System:  Fig.  14,  with  Meter  in  Service 36 

17.  System:  Developing  Detail  for  Fig.  14 36 

.     18.  System:  Rearrangement  of  Fig.  14  to  Suit  Detail 37 

19.  System  (Sample):  Water  Lines,  3  to  4  Division  Plant 39 

20.  System:  Fire  and  Low  Pressure  Water  Service 40 

21.  System:  Fire  Main  Supplying  Feed  Water  Heater 41 

22.  System  (Sample):  Condenser  Circulating  Water 42 

CHAPTER    IV. 

CONDENSERS  AND  HEATERS 44 

Fig.  23.  System  (Complex):  Artesian   Water,    Chemical   Treatment, 

Cooling  Tower  and  Condensers i ..-.  44 

24.  System:  Artesian  Water,   Surface  Condensers  and  Cooling 

Tower 46 

vii 


Viii  CONTENTS. 

PAGE 

Fig.  25.  System:  Controlling  Feed  Pump,  Open  Heater  and  Surface 

Condenser 4^ 

26.  System:  Controlling  Feed  Pump,  Open  Heater  and  Jet  Con- 

denser   49 

27.  System:  Air  from  Elevated  Jet  Condenser  to  Dry  Vacuum 

Pumps 5° 

28.  System:  Removing  Air  from  Counter  Current  Surface  Con- 

densers   51 

29.  System:  Removing  Air  from  Direct  Current  Surface  Con- 

densers    52 

30.  System:  Improperly  Arranged  for  Removing  Air  from  an 

Induction  Open  Heater  of  Insufficient  Steam  Supply 53 

31.  System:  Properly  Arranged  to  Remove  Air  in  Open  Heater  of 

Insufficient  Steam  Supply 53 

32.  System:  Passing  Entire  Volume  Steam  through  Open  Heater  53 

33.  System:  Passing   Entire   Volume    Steam    through    Closed 

Heater 54 

34.  System:  Passing  Small  Volume  Steam  into  Closed  Heater..  .  54 

35.  System:  Passing  Entire  Steam  Improperly  through  Closed 

Heater 54 

CHAPTER  V. 

LIVE  STEAM  DRIPS 55 

Fig.  36.  System:  Gravity  Return  of  Steam  Drips 55 

37.  System:  Return  of  Steam  Drips  by  Pump 57 

38.  System:  Discharge  of  Steam  Drips  to  Heater  by  Trap 57 

39.  System:  Return  of  Steam  Drips  by  Pulsation  of  Feed  Pump  58 

40.  System:  Steam,  Boiler  Feed  and  Gravity  Drip  Return 60 

41.  System:  Steam,  Boiler  Feed  and  Receiver  Pump  Drip  Return  62 

42.  System:  Collecting  Steam  Drips  of  Slightly  Varying  Pressures  63 

43.  System:  Supporting  Engine  Reheaters  to  Give  Sufficient  Head 

for  Drip  Flow 64 

44.  System  (Sample) :  Steam  and  Gravity  Drip  Return  to  Boilers  65 

CHAPTER   VI. 

BLOW-OFF  AND  EXHAUST  PIPING 67 

Fig.  45.  System  (Sample):  High  Pressure  Blow-off  Lines 67 

46.  System  (Sample):  Low  Pressure  Blow-off  Lines 72 

47.  System:  Engine  Exhaust  to  Condensers  and  Exhaust  Main 

with  Undesirable  Features 73 

48.  System  (Sample):  Engine  Exhaust  to  Condensers  and  Ex- 

haust Main  without  Undesirable  Features 74 

49.  System:  Exhaust  from  Auxiliaries;  Improperly  Laid  Out...  .  76 

50.  System:  Exhaust  from  Auxiliaries;  Properly  Laid  Out.  ...  77 

51.  System:  Same  as  Fig.  50  with  Modified  Position  of  Parts.  . .  77 

52.  System  (Sample):  Exhaust  from  Auxiliaries  to  Heater 78 


CONTENTS.  ix 
CHAPTER    VII. 

PAGE 

AIR  AND  OILING  SYSTEMS 79 

Fig.  53.  System  (Sample) :  Compressed  Air 80 

54.  System:  Feeding  Cylinder  Oil  from  Tank  to  Engine 81 

55.  System:  As  Shown  54,  Applied  Systematically  in  a  Plant. .  .  82 

56.  System:  Oiling  Journals  by  Using  Tanks  and  Compressed  Air  83 

57.  System:  Oiling  Journals  by  Using  Pump  and  Governor 84 

58.  System:  Measuring  Daily  Consumption  of  Cylinder  Oil.  ...  87 

59.  System:  Independent  Hand  Supply  Oiling  System  in  Con- 

junction with  Pipe  Line  System 93 

60.  System:  Oil  Drfp  Return,  Filters,  and  Air  Pressure  Tanks.  .  94 

CHAPTER    VIII. 

OIL  AND  WATER  PURIFYING  SYSTEMS 97 

Fig.  61.  System:   Gravity  Pressure  Oil  Supply,  with  Precipitation 

Tanks 100 

62.  System  (Sample):  Shown  Fig.  61   and  Arranged  for  Con- 

tinuous Service 103 

63.  System:  Intermittent  Water  Treating  Plant 105 

64.  System  (Sample):  for  Water  Treating  Plant. 106 

65.  System:  Continuous  Water  Treating  Plant 107 

66.  System:  Pressure  Water  Treating  Plant 108 

CHAPTER   IX. 

PIPING  DETAILS:  METHOD  OF  CLASSIFICATION 109 

CHAPTER   X. 

LIVE  STEAM  DETAILS. 

Ai.     Header  or  Main in 

A2.     Engine  Branches TV- 115 

A3.     Boiler  Branches 118 

A4.     Auxiliary  Main 124 

A5.     Branch  to  Feed  Pumps 124 

A6.     Branch  to  Fire  Pumps 124 

Ay.     Branch  to  Circulating  Pumps 124 

A8.     Branch  to  Dry  Vacuum  Pumps 124 

A9.     Branch  to  Wet  Vacuum  Pumps 124 

Aio.  Branch  to  Automatic  Pumps 124 

An.  Branch  to  Stoker  Engine 124 

Ai2.  Branch  to  Stack  Fan  Engine 124 

Ai3.  Branch  to  Conveyor  Engine 124 

Ai4.  Branch  to  Crusher  Engine 124 

Ai5.  Branch  to  Stoker  Controller  and  Rams 131 

Ai6.  Branch  to  Tank  Pump 135 


X  CONTENTS. 

PAGB 

Ai7.   Branch  to  Smoke  Consumer  or  Oil  Burner 13° 

Ai8.  Branch  to  Soot  Blowers 13° 

Aig.  Branch  to  By-pass  to  Exhaust  Heater  or  Heating  System 137 

A20.  Branch  to  Whittle I38 

A2i.  Branch  to  Kjector  Vacuum  Traps 139 

A22.  Branch  to  Heating  System 139 

A23.  Branch  to  Cleaner  for  Oil  Tanks 141 

A24.  Branch  from  Header  to  Atmosphere 142 

A25.  Branch  to  Damper  Regulator 142 

A26.  Branch  to  Oil  Filter 142 

A27.  Branch  to  Blow-out  Oil  Drip  Main 143 

A28.  Branch  to  Water  Column  and  Column  Connections 144 

A29.  Branch  to  Steam  Gages 151 

A3o.  Branch  from  Safety  Valves,  through  Roof 154 

AJI.  Branch  for  Heating  Lavatory  Water 157 

A32.  Branch  to  Prevent  Freezing  Roof  Conductors 158 

A33.  Branch  to  Low-Pressure  Cylinder 159 

A34.  Branch  to  Engine  Cylinder  Jackets 162 

A35-  Branch  to  Live  Steam  Purifier 162 

A36.  Branch  to  Other  Buildings 163 

A37.  Branch  to  Heater  Coil  in  Engine  Receiver 165 

A38.  Branch  to  and  from  Superheaters 166 

A39.  Branch  to  Turbines 168 

CHAPTER  XI. 
VACUUM  EXHAUST  DETAILS. 

Bi.  Main 170 

62.  Branch  to  Engines 170 

63.  Branch  to  Condenser 182 

64.  Branch  to  Grease  Extractor 184 

65.  Branch  to  High-Pressure  Cylinder 186 

B6.  Branch  to  Auxiliaries 187 

67.  Branch  to  Cylinder  Relief  Valves 191 

CHAPTER  XII. 

ATMOSPHERIC  EXHAUST  DETAILS. 

Ci.  Main jp^ 

C2.  Branch  to  Engine jpj 

C3-  Branch  to  Atmosphere !g6 

C4.  Auxiliary  Main jgg 

C5-  Auxiliary  Main  to  Atmosphere 199 

C6.  Branch  to  Heater 200 

C7.  Branch  to  Feed  Pumps.  . 201 

C8.  Branch  to  Fire  Pumps 2O1 

C9.  Branch  to  Circulating  Pumps 201 


CONTENTS.  xi 


Cio.  Branch  to  Dry  Vacuum  Pumps 201 

Cn.  Branch  to  Wet  Vacuum  Pump 201 

Ci2.  Branch  to  Automatic  Pump 201 

Ci3-  Branch  to  Stoker  Engine •  201 

€14.  Branch  to  Stack  Fan  Engine 201 

€15.  Branch  to  Conveyor  Engine 201 

Ci6.  Branch  to  Crusher  Engine 201 

Ciy.  Branch  to  Oil  Pump 201 

Ci8.  Branch  to  Stoker  Operators 203 

Cip.  Branch  to  Roof  Conductors  to  Prevent  Freezing 207 

C2o.  Branch  to  Heating  System 207 


CHAPTER   XIII. 

BOILER  FEED  DETAILS. 

Di.     Main 214 

D2.     Branches  to  Boilers 214 

03.  Branches  from  Pumps. 228 

04.  Branches  to  and  from  Economizers 229 

05.  Branches  to  and  from  Closed  Exhaust  Heater 231 

D6.     Branches  to  and  from  Closed  Vacuum  Heater. 231 

07.     Branches  to  and  from  Closed  Live  Steam  Purifier 232 

D8.     Branches  to  and  from  Injector 234 

Dg.     Branches  to  and  from  Meter 234 

Dio.  Branches  to  Hot  Water  Plumbing  Fixtures 236 

CHAPTER   XIV. 

AUXILIARY  BOILER  FEED  DETAILS. 

Ei.  Main 238 

£2.  Branch  to  Boilers 238 

£3.  Branch  from  Pumps 239 

£4.  Branch  to  Hydraulic  Tube  Cleaner 240 


CHAPTER   XV. 

FEED  AND  FIRE  PUMP  SUCTION  DETAILS. 

Fi.  Main 243 

F2.  Branch  to  Pumps 249 

F3.  Branch  from  Heater 250 

F4.  Branch  from  Hot  Well 251 

F5.  Branch  from  Intake 255 

F6.  Branch  from  City  Water  Main 255 

Fy.  Branch  from  Economizer 256 

F8.  Branch  from  Storage  Tank  or  Basin 256 


xii  CONTENTS. 

CHAPTER   XVI. 

PAGE 

HEATER  WATER  SUPPLY  DETAILS. 

Gi.  Branch  from  Condenser 259 

G2.  Branch  from  Intake 264 

03.  Branch  from  City  Water  Mains 266 

04.  Branch  from  Low-Pressure  System 267 

65.  Branch  from  Special  Pumps 268 

G6.  Branch  from  Injection  to  Surface  Condenser 269 

CHAPTER   XVII. 

LOW-PRESSURE  WATER  DETAILS. 

Hi.     Main 271 

H2.     Branch  from  Pumps 272 

H3.     Branch  to  and  from  Water  Tank 272 

H4.     Branch  to  Heater 277 

H5.     Branch  to  Engine  Journals 278 

H6.     Branch  to  Dry  Vacuum  Pump 279 

H7.     Branch  to  Pump  Priming  Pipes 280 

H8.     Branch  to  Hose  Connections 281 

H9.     Branch  to  Oil  Filter  and  Tanks 282 

Hio.  Branch  to  Grease  Extractor 282 

Hi i.  Branch  to  Cooling  Boxes  at  Furnace 283 

Hi2.  Branch  to  Economizer  Heating  System 285 

Hi3.  Branch  to  Plumbing  Fixtures 286 

Hi4.  Branch  to  Separate  Buildings 287 

CHAPTER   XVIII. 

CONDENSER  COOLING  WATER  DETAILS. 

11.  Intake  from  Waterway , 289 

12.  Discharge  from  Condenser 308 

13.  Cooling  Water  Main 317 

14.  Cooling  Water  Branch  from  Pumps 317 

15.  Cooling  Water  Branch  to  Condensers 317 

16.  Cooling  Water  Branch  to  Feed  and  Fire  Pumps 320 

17.  Cooling  Water  Branch  to  Low-Pressure  System 320 

18.  Cooling  Water  from  Condenser  for  Feed  Pump 320 

IQ.  Cooling  Water  to  and  from  Cooling  Tower 322 

CHAPTER   XIX. 
CONDENSATION,  AIR  AND  VACUUM  LINE  DETAILS. 

Ji.  Condensation  and  Air  Line  from  Condenser 328 

J2.  Dry  Vacuum  Main 333 

J3.  Dry  Vacuum  Branch,  Main  to  Pump 333 

J4.  Dry  Vacuum  Branch,  Pump  Discharge  to  Atmosphere 333 


CONTENTS.  xiii 

PAGE 

J5.  Dry  Vacuum  Branch,  Pump  Suction  to  Atmosphere 333 

J6.  Condensation  Main 338 

Jy.  Condensation  Branch  from  Pump  to  Main , 338 

J8.  Condensation  Branch  from  Main  to  Heater 338 

JQ.  Condensation  Branch  from  Pump  to  Boilers 338 

CHAPTER   XX. 

CITY  WATER  PIPING  DETAILS. 

Ki.     Main 342 

K.2.     Branch  to  and  from  Meter 347 

K3.     Branch  to  Plumbing  Fixtures 347 

K4.     Branch  to  Low-Pressure  Water  System 348 

K5.     Branch  to  Boiler  Feed  Main 349 

K6.     Branch  to  Pump  Suction. 350 

K7.     Branch  to  Heater 351 

K8.     Branch  to  Fire  System 352 

KQ.     Branch  to  Priming  Pipes 352 

Kio.  Branch  to  Hydraulic  Elevators 352 

Kn.  Branch  to  Engine  Journals 352 

Ki2.  Branch  to  Pressure  Oil  Tanks 353 

Ki3.  Branch  to  Damper  Regulator 353 

Ki4.  Branch  for  Drinking  Purposes 354 

Ki5.  Branch  to  Other  Buildings. 354 

CHAPTER   XXI. 

ARTESIAN  WATER  PIPING  DETAILS. 

Li.  Branch  to  Pump 355 

L2.  Branch  to  Storage  Tank 355 

L3.  Branch  to  Power  House 361 

L4.  Branch  to  Other  Buildings , 362 

L5.  Branch  to  Fire  Mains 363 

L6.  Branch  to  Condensers 363 

L7.  Branch  to  Air  Lifts 366 

L8.  For  High  Buildings 368 

CHAPTER   XXII. 

FIRE  SERVICE  PIPING  DETAILS. 

Mi.  Mains 370 

M2.  Branch  to  Hydrants 379 

M3.  Branch  to  Interior  Connections 380 

M4.  Branch  to  Roof 383 

M5.  Branch  from  City  Supply 385 

M6.  Branch  to  Low-Pressure  Service 386 

M7.  Branch  to  Oil  Room 387 


XJV  CONTENTS. 

CHAPTER   XXIII. 

WATER  TREATMENT  APPARATUS  AND  BPING  DETAILS. 

Ni.  Water  Supply ' 3^9 

Na.  Boiler  Supply 

N3.  Treatment  after  Reaching  the  Boiler 

N4.  Minor  Connections.  . 

CHAPTER   XXIV. 

HYDRAULIC  ELEVATOR  PIPING  DETAILS. 

01.  Water  Line  to  Valve *02 

02.  Water  Line  to  Ram 

03.  Waste  Water  to  Pump  Suction,  Sewer  or  Reservoir 402 

CHAPTER   XXV. 
AIR  LINE  DETAILS. 

Pi.  Main 407 

P2.  Branch  for  Blowing  Out  Electrical  Apparatus 408 

?3.  Branch  for  Oiling  System 408 

P4.  Branch  for  Fire  Protection 4™ 

P5.  Branch  for  Signal  Whistles 4io 

CHAPTER   XXVI. 
STEAM  DRIP  DETAILS. 

Qi.     Branch  from  Steam  Mains 4" 

Q2.     Branch  from  Separators 4T3 

Q3.     Branch  from  Boiler  and  Engine  Steam  Branches 4J4 

Q4.     Branch  from  Auxiliary  Steam  Main  and  Gravity  Return 414 

Q5.     Branch  from  Pump  Steam  Branches 416 

Q6.     Branch  from  Pump  Steam  Cylinders 417 

Qy.     Branch  from  Engine  Cylinders  and  Jackets   417 

Q8.     Branch  from  Engine  Receiver  and  Reheater 4T8 

Qg.     Branch  from  Steam  Loop  419 

Qio.  Branch  from  Automatic  Pump 421 

Qn.  Branch  from  Exhaust  Steam  Main  and  Branches 422 

Qi2.  Branch  from  Vacuum  Separator  and  Steam  Traps 422 

Qi3.  Branch  from  Outside  Buildings 423 

Qi4.  Miscellaneous 428 

CHAPTER   XXVII. 
OIL  AND  DRIP  PIPING  DETAILS. 

Ri.  Mains 429 

R2.  Branches  to  Cups  and  Machines , 431 

R3.  Branches  for  Oil  Pumps 436 

R4.  Branches  for  Filters  and  Purifiers 439 

R5.  Branches  for  Oil  Storage 445 

R6.  Branches  for  Hand  Devices 446 


CONTENTS.  XV 
CHAPTER   XXVIH. 

PAGE 

BLOW-OFF  PIPING  DETAILS. 

Si.  Main 449 

82.  Branches  from  Boilers 451 

83.  Branches  from  Economizers 453 

84.  Branches  from  Heaters,  Purifiers,  etc 454 

85.  Branches  from  Steam  Traps  and  Bleeders 455 

86.  Blow-off  Tanks 455 

CHAPTER   XXIX. 

GREASE  SEWER  DETAILS. 

Ti.  Main 458 

T2.  Branch  from  Engines 459 

T3.  Branch  from  Pumps 460 

T4.  Branch  from  Grease  Extractors 461 

TS.  Branch  to  Precipitation  Tank 461 

CHAPTER   XXX. 

TILE  SEWER  DETAILS. 

Ui.     Main 462 

U2.     Branch  from  Roof  Conductors 462 

U3.     Branch  from  Plumbing  Fixtures 463 

U4.     Branch  from  Floor  Drains 464 

U5.     Branch  from  Ash  Wetting  Floor 467 

U6.     Branch  from  Boiler  Washouts 467 

U7.     Branch  from  Economizers  and  Heaters 469 

U8.     Branch  from  Blow-off  and  Grease  Tank 469 

U9-     Branch  from  Pumps 469 

Uio.  Branch  from  Filters 470 

Un.  Branch  from  Drain  Tile  Sewers 470 

Ui2.  Branch  from  Sumps .^ 471 

CHAPTER    XXXI. 

SUNDRY  MINOR  PIPING  DETAILS. 

Vi.  Gage  Connections 473 

V2.  Water  Column  and  Feed  Regulator  Connections 474 

¥3.  Damper  Regulator  Connections 475 

¥4.  Relief  Valve  Connections 477 

¥5.  Pressure  or  Speed  Regulator  Connections 477 

V6.  Cylinder  Lubricator  Connections . 479 

¥7.  Steam  Trap  Connections 479 

V8.  Plugged  Openings  and  Air  Vents 480 


STEAM    POWER    PLANT 
PIPING    SYSTEMS. 


CHAPTER  'I;."; 
INTRODUCTION. 

THE  first  chapter  of  this  work  is  devoted  to  the  origin  and 
results  of  improper  piping,  and  also  explains  the  necessity  of 
better  piping  systems  and  suggests  methods  of  securing  better  pipe 
work  and  piping  systems  by  employing  different  methods  in  engi- 
neering offices.  The  chief  requisite  in  pipe  work  engineering  is 
so  to  design  as  to  permit  repairs  of  disabled  lines  without  inter- 
fering with  the  regular  service  of  the  plant.  There  are  but  few 
requirements  to  insure  continuous  operation,  but  these  few  must 
be  very  carefully  considered  and  well  safe-guarded,  for  no  matter 
how  careful  the  station  attendant  may  be  he  cannot  foresee  every 
possible  difficulty.  It  is  only  by  experience  with  trouble  that  we 
learn  to  avoid  it,  and  it  is  absurd  to  assume  that  any  man  has 
experienced  every  difficulty  and  mishap  that  is  possible  in  a  steam 
plant  so  that  by  careful  inspection  he  could  avert  any  such  diffi- 
culty that  might  arise. 

Moreover,  a  plant  should  not  be  laid  out  with  a  system  that  ne- 
cessitates repairs  after  the  plant  is  shut  down,  say  between  i  A.  M. 
and  5  A.  M.,  for  it  is  not  reasonable  to  expect  an  operating  man  to 
take  much  interest  in  his  station  work  if  he  must  work  night  and 
day  to  keep  the  plant  in  good  order.  If  a  plant  is  to  be  well  kept 
up  it  must  be  so  designed  that  repairs  can  be  made  whenever  the 
chief  can  find  spare  help  to  do  the  work;  this  may  happen  at  10 
A.  M.  one  day  and  possibly  3  P.  M.  the  next  day.  Repairs  that  can  be 
made  only  at  certain  hours  cause  such  disturbance  in  the  general 
organization  of  the  men  that  it  takes  a  day  or  two  before  matters 
fall  back  into  their  regular  routine  again.  This  disturbance  of 


2  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

regular  duties  means  increased  expense  and  it  discourages  the  men, 
and  after  a  time  the  station  will  show  conspicuously  that  it  is  run 
down.  The  first  to  receive  the  blame  for  this  is  the  operator, 
whereas  in  reality  it  should  fall  upon  the  designer.  Any  station 
manager  who  has  found  it  necessary  to  make  repeated  changes 
in  station  operators,  who  has  paid  fair  salaries  and  who  has  failed 
to  obtain  satisfactory  results,  can  blame  the  entire  difficulty  to 
faulty  design: .  A  station  operator  very  naturally  objects  to  leaving 
his  home  at  'I  "o'clock  in  thie  morning  to  make  some  slight  repair  in 
order  t&  kesejat  fr&'statioh  ih&  neat  condition.  His  incentive  when 
he  makes 'night  rep'airs  arise's  from  fear,  not  pride;  fear  of  a  mishap 
that  may  affect  the  sum  he  receives  in  his  pay  envelope.  What  a 
strong  contrast  is  exhibited  between  a  neat,  well  kept  plant  and  a 
dirty,  dilapidated  looking  one!  If  we  visit  the  former  we  are 
informed  by  the  chief  sitting  at  his  desk,  possibly  studying  his 
station  records,  that  everything  is  running  beautifully,  and  upon 
making  a  trip  through  the  plant  we  may  note  that  an  intelligent 
looking  assistant  is  making  some  joints  on  a  steam  line,  and  in  the 
boiler  room  the  fireman  is  placing  packing  in  one  of  the  reserve 
pumps.  The  general  appearance  of  these  men  is  neat  and  they 
are  attending  cheerfully  to  their  work. 

In  the  dilapidated  station  we  find  steam  blowing  everywhere  and 
a  dirty  looking,  tired  out  man  getting  up  from  an  old  box  just  long 
enough  to  fill  the  oil  cups  or  throw  some  coal  into  the  furnace  and 
then  sitting  down  again.  Off  in  a  corner  we  find  the  chief  taking 
a  nap,  for  he  says,  "I  was  up  most  of  the  night  trying  to  make  a 
joint  in  that  old  steam  line."  When  asked  how  things  are  run- 
ning, he  will  say,  "The  old  station  is  going  to  pieces;  we  have 
all  kinds  of  trouble." 

In  the  first  case  the  men  are  all  working;  they  appear  intelligent 
and  cheerful,  and  everything  is  running  smoothly.  In  the  other 
case  no  one  seems  to  be  working,  the  men  take  no  interest  in  their 
work  and  the  station  has  become  dilapidated.  The  fault  lies  in 
the  design  of  the  station.  Conscientious,  capable  men  are  in 
demand  and  they  select  their  positions.  None  of  them  wants  to 
come  back  nights  and  work  on  a  dirty,  hot  job.  The  result  is  that 
good  men  cannot  be  obtained  for  poorly  designed  plants,  and  conse- 
quently such  plants  run  down  for  the  lack  of  intelligent  care  by 
men  who  take  an  interest  in  their  work.  The  first  cost  of  making 
ample  provisions  for  all  contingencies  will  amount  to  so  many 


INTRODUCTION.  3 

dollars  and  will  readily  be  appreciated  by  the  purchaser.  But  why, 
if  an  engineer  is  familiar  with  station  operation,  does  he  allow 
the  purchaser  to  see  only  the  initial  cost?  If  he  cannot  succeed 
in  persuading  the  purchaser  to  abandon  a  design  which  would 
necessitate  night  repairs,  it  would  be  better  for  the  engineer  not 
to  be  identified  with  the  undertaking.  When  an  engineer  loses 
control  of  an  undertaking  and  is  constrained  to  accept  details 
which  he  knows  are  wrong,  it  is  far  better  for  him  and  for  his 
reputation  as  a  designer  to  go  on  record  as  opposing  the  design  and 
to  relinquish  all  connection  with  the  work.  Instead  of  being 
known  as  the  engineer  who  designed  the  monstrosity,  he  had 
better  be  known  as  the  engineer  who  refused  to  do  so. 

Unfortunately,  the  cause  of  the  greater  part  of  inferior  station 
pipe  work  can  be  traced  directly  to  the  engineers  themselves. 
There  is  no  other  portion  of  station  work  that  affords  the  engineer 
a  similar  opportunity  of  showing  his  knowledge  of  station  require- 
ment, none  that  requires  as  much  time  properly  to  design,  and 
none  that  is  more  certain  to  develop  the  station  into  a  run-down, 
expensive  plant  to  operate,  or  the  reverse.  The  piping  and  piping 
system  and  the  electrical  wiring  are  the  only  features  in  power 
station  design  that  really  require  extensive  engineering  knowledge. 
The  machines  required  are  designed  by  their  builders  for  given 
capacities,  and  if  the  piping  and  piping  system  are  not  properly 
cared  for  by  the  engineer  he  fails  to  do  that  work  which  is  purely 
his.  In  other  words,  the  engineer  is  either  incapable  or  else  he  is 
conducting  his  engineering  office  on  a  purely  commercial  basis  and 
puts  as  little  time  and  care  into  the  project  as  is  possible.  A  sys- 
tem of  paying  for  engineering  knowledge  according  to  the  amount 
of  money  a  man  can  spend  is  certainly  far  from  an  equitable  basis. 
The  engineer  must  then  make  some  show  for  his  money.  He  will 
possibly  resort  to  a  display  of  inexpensive  drawings  and  allow  the 
builders  to  furnish  the  decorative  features  of  the  plant.  The 
piping  drawings  may  be  prepared  "  so  as  to  let  the  contract  'in 
two  weeks,"  and  they  are  generally  turned  over  to  an  unskilled 
draftsman.  The  percentage  system  is  wrong;  but  it  is  in  vogue 
and  will  unquestionably  remain  in  vogue  for  some  time.  But 
some  better  method  of  designing  pipe  work  is  badly  needed,  and 
already  steps  in  the  right  direction  are  being  taken,  for  we  can 
find  men  in  the  large  piping  establishments  who  are  now  making  a 
special  study  of  piping  details  and  who  design  new  details  which 


4  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

take  the  place  of  those  furnished  by  the  engineers.  The  shop 
drawings  have  dimensions  center  to  face,  flange,  templates,  etc., 
all  of  which  are  standard  in  each  particular  shop. 

As  it  is  necessary  for  fitters  to  make  these  details,  this  fact 
suggests  a  method  of  letting  contracts  for  pipe  work.  The 
method  is  one  that  would  enable  engineers  to  let  contracts  for 
piping  with  the  least  possible  expenditure  of  labor,  although 
it  entails  more  time  for  drafting  on  the  part  of  the  fitter;  but  the 
saving  effected  in  pipe-work  detail  determined  by  the  fitter  rather 
than  by  the  engineer  will  more  than  compensate  for  the  extra 
cost  of  drafting.  Each  shop  knows  best  that  style  of  work  for 
which  it  is  best  fitted,  and  what  it  can  construct  most  economically, 
and  by  allowing  the  fitters  to  take  advantage  of  these  economies 
they  can  make  lower  estimates  for  the  completed  work  even  though 
they  are  compelled  to  furnish  detail  drawings.  The  details  will 
be  subject  to  the  approval  of  the  engineer  in  the  same  way  as  with 
structural  details.  The  engineer  should  ask  the  fitters  to  furnish 
all  pipe  supports  and  special  features,  such  as  steam  gages,  safety 
valves,  etc.,  as  well  as  pipe  covering,  as  the  engineer  would  not 
have  any  details  to  show  these. 

The  engineer  should  specify  either  the  make  or  the  style  of  the 
valves,  fittings,  pipe,  etc.,  for  each  system.  He  should  also  fur- 
nish drawings  showing  the  location  of  the  boilers,  engines,  pumps, 
etc.,  and  well-developed  and  complete  station  diagrams,  as  will 
be  shown  in  a  future  chapter.  The  pumps  should  be  located  to 
conform  to  the  diagram  of  station  piping  as  far  as  possible.  In 
short,  the  engineer  would  develop  the  entire  piping  system,  deter- 
mine sizes  and  number  of  parts,  but  allow  the  pipe  contractor  to 
determine  the  exact  location  of  lines  and  branches,  as  well  as  the 
supports;  a  class  of  work  that  very  few  engineers  are  sufficiently 
posted  on  or  wish  to  take  the  time  to  do  well.  Instead  of  the 
engineer  laying  out  pipe  details  that  will  be  redesigned  by  the 
fitter,  he  will  save  expense  both  to  himself  and  to  his  client  by 
confining  his  efforts  to  designing  the  station  system  and  to  obtain- 
ing bids  from  those  fitters  who  are  known  to  have  piping  engineers 
who  can  properly  detail  piping. 

The  result  of  this  method  of  handling  the  complex  problems  in- 
volved in  pipe  work  will  be  that  the  engineer  will  give  his  entire 
time  and  study  to  the  station  system,  a  class  of  work  for  which  he 
is  best  suited,  and  the  piping  contractor  will  use  more  time  and 


INTRODUCTION.  5 

skill  in  planning  the  different  lines  and  details  than  the  engineer 
will  be  able  or  willing  to  devote  to  it.  The  work  when  com- 
pleted would  cost  less  money  and  would  be  more  creditable  to  all 
concerned  than  if  all  the  details  devolved  upon  the  engineer.  The 
pipe  contractor  of  to-day  is  no  longer  the  petty  contractor  of 
former  years.  His  contract  runs  into  large  figures  and  he  employs 
the  highest  skilled  labor  to  expedite  his  work.  His  erecting  labor 
is  very  high-priced  and  he  can  readily  save  the  expense  of  a  capable 
piping  engineer  by  simplifying  his  field  work,  though  in  many 
cases  it  would  slightly  increase  the  cost  of  shop  work,  on  account 
of  the  practical  details  that  a  purely  office  man  never  learns. 
Structural  iron  shops  have  employed  this  method  of  redesigning 
work  to  such  an  extent  that  power  station  engineers  do  not  even 
attempt  to  detail  steel  work,  but  give  general  requirements  to  steel 
contractors  and  allow  them  to  make  their  details  after  receiving 
the  contract,  and  then  submit  them  to  the  engineer  for  his  approval. 
In  the  case  of  an  extremely  large  undertaking  an  engineer  will 
sometimes  engage  a  structural  engineer  to  design  and  detail  the 
work,  but  will  keep  him  only  while  he  has  a  large  amount  of 
such  work  on  hand.  He  cannot  afford  to  retain  a  specialist  after 
the  work  is  designed  and  the  specialist  cannot  afford  to  undertake 
such  temporary  work.  The  result  is  that  the  specialists  of  ability 
are  found  with  the  manufacturers,  not  with  the  engineers. 

The  power  station  engineer  is  virtually  the  assembly  engineer 
and  his  training  has  been  that  of  an  examiner  and  a  judge.  He  is 
not  a  specialist  in  any  line  of  manufacture  and  when  he  undertakes 
such  work  it  is  very  much  in  the  nature  of  an  experiment.  Some 
years  ago  the  engineers  designed  the  boilers,  not  because  they  were 
specially  fitted  for  this  work,  but  because  the  boiler  business  had 
not  developed  to  such  an  extent  that  the  manufacturers  required 
skilled  boiler  designers  in  their  employ.  But  this  is  no  longer  the 
case.  Manufacturers  now  employ  engineers  who  make  a  specialty 
of  boiler  designing  and  the  power  station  engineers  make  no  attempt 
to  design  boilers.  The  same  will  be  the  case  with  pipe  work  and  it 
will  undoubtedly  be  but  a  short  time  before  piping  details  will  be 
developed  by  the  manufacturer  and  not  by  the  power  station 
engineer.  Not  until  then  will  we  find  good  serviceable  pipe  work 
installed  in  the  various  plants  under  construction. 

The  introduction  of  piping  system  diagrams,  and  the  letting  of 
contracts  based  upon  them,  will  be  the  first  move  toward  developing 


6  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

this  method.  It  will  then  devolve  upon  the  piping  contractor  to 
design  the  details  and  he  will  no  longer  be  able  to  evade  the  re- 
sponsibility of  bad  pipe  work  design.  His  reputation  will  then 
depend  upon  his  design  as  well  as  upon  his  workmanship.  To 
protect  himself  he  will  be  compelled  to  design  his  work  more 
thoroughly  than  it  could  or  would  be  done  by  the  power  station 
engineer.  As  previously  stated  the  practice  of  relegating  the 
details  of  pipe  work  to  the  fitter  is  in  no  way  detrimental  to  the 
engineer  or  to  the  purchaser.  The  engineer  could  then  devote 
his  time  to  the  system,  which  is  generally  overlooked;  the  fitter 
would  lay  out  a  neater  and  more  reliable  job  and  one  costing  less 
money  to  construct;  when  completed  there  would  be  more  to  show 
for  the  labor  expended  than  by  the  present  method  of  indifferent, 
incompetent  or  hasty  work  laid  out  by  the  power  station  engineer. 
Instead  of  making  a  study  of  how  to  connect  flanges  to  pipe,  the 
engineer  should  devote  his  thought  and  study  to  systems,  as  for 
the  system  alone  will  he  be  held  responsible.  The  contractor  will 
assume  the  responsibility  of  how  to  attach  flanges  to  pipe  and  it 
will  have  to  be  done  his  way  if  he  does  assume  the  responsibility. 
An  engineer  must  not  expect  to  hold  a  contractor  responsible 
for  his  own  notions  in  regard  to  certain  details.  If  a  contractor 
is  to  be  held  responsible  for  results  he  must  be  permitted  to  use 
such  details  as  he  knows  will  accomplish  what  is  demanded  of  him. 
In  inviting  bids  it  is  not  necessary  to  state  what  details  the  man- 
ufacturer shall  use,  but  it  is  advisable  to  ask  him  to  state  the  details 
he  proposes  to  furnish.  This  can  be  clearly  outlined  in  specifica- 
tions, using  a  loose  data  sheet  for  the  bidder  to  fill  in,  covering  such 
information  as  the  engineer  wishes  to  obtain.  If  such  a  system  re- 
quired additional  labor  on  the  part  of  the  engineer,  or  cost  more 
money,  or  was  less  effective,  the  engineer  would  undoubtedly  con- 
tinue to  design  his  own  pipe  details.  But  since  the  engineer  and 
his  clients  have  much  to  gain  and  virtually  nothing  to  lose  through 
the  method  here  outlined,  it  should  not  require  much  argument  to 
prove  the  desirability  of  this  method  becoming  common  practice. 


CHAPTER    II. 
PIPING   DIAGRAMS. 

THE  laying  out  of  piping  diagrams  is  the  first  move  necessary  in 
determining  the  equipment  required  for  a  power  station.  To 
determine  sizes  of  machinery,  boilers,  etc.,  before  the  pipe  system 
is  laid  out  is  wholly  wrong,  as  by  so  doing  there  can  be  no  defined 
system,  but  merely  the  connecting  of  a  hole  in  a  boiler  with  a  hole 
in  an  engine.  Almost  any  novice  is  able  to  say,  "We  shall  want 
so  many  units  of  a  certain  size  and  so  many  other  units  of  another 
size."  But  why  should  we  expect  systematic  results  from  a  mere 
guess  ?  When  the  question  arises  how  to  determine  the  machinery 
for  a  plant,  shall  we  find  a  well  conceived  system  laid  out  to  deter- 
mine it?  Unfortunately  for  all  concerned  the  almost  universal 
method  is  to  order  the  machinery  by  rule  of  thumb,  and  then  turn 
the  piping  work  over  to  almost  anybody  in  the  office  that  can  make 
the  drawings,  and  never  even  stop  to  think  about  what  system  is  to 
be  used.  In  fact,  if  the  question  be  asked  in  nine  out  of  every  ten 
engineering  offices,  what  their  system  is  of  connecting  up  the 
apparatus,  they  would  most  certainly  hesitate  before  endeavoring 
to  make  an  answer.  When  referring  to  piping  we  invariably  hear 
the  expression,  "boilers  connected  up  so  and  so,"  and  the  same  with 
other  apparatus.  The  thought  is  wrong,  and  not  until  "piping"  is 
recognized  as  the  system  of  the  station  and  given  first  consideration, 
will  we  find  better  or  more  reliable  installations. 

The  diagrams  illustrated  indicate  a  form  of  drawing  which  is 
quick  to  make  and  readily  understood.  The  relative  location  of 
apparatus  may  be  different  from  the  diagram,  but  the  connections, 
etc.,  would  be  brought  to  the  same  relative  point  as  shown.  The 
diagram  should  be  the  first  drawing  made  of  the  station,  and  after 
determining  the  system  the  proper  number  and  size  of  units  can  be 
established.  The  diagram  of  all  station  piping  should  be  framed 
and  placed  in  a  conspicuous  place,  so  station  attendants  will  become 
familiar  with  the  system.  Any  changes  made  in  piping  should  be 
also  shown  on  these  diagrams.  It  matters  not  how  crude  the  piping 

7 


8  STEAM  POWER  PLANT  PIPING  SYSTEAfS. 

system  may  be  in  a  plant,  a  diagram  should  be  in  plain  view  show- 
ing it  clearly. 

A  simple  method  of  laying  out  a  diagram  is  to  make  detached 
free-hand  sketches  of  each  line,  such  as  main  steam  line,  main 
exhaust,  blow-off,  etc.,  and  after  carefully  considering  all  the  lines  a 
complete  diagram  can  be  more  readily  laid  out.  A  scale  drawing 
is  neither  desirable  nor  practicable.  While  laying  out  the  diagram 
it  is  also  policy  to  lay  out  sketches  of  various  details  to  be  retained 
as  references.  These  various  references  determine  many  of  the 
details  that  require  decision  before  writing  specifications  for  appara- 
tus. Some  of  the  connections  shown  on  the  diagrams  may  appeal 
to  the  reader  as  being  rather  unusual;  the  fact  that  they  appear  so 
is  the  desired  demonstration  of  the  value  of  the  diagram.  A  full 
comprehension  of  the  entire  problem  is  possible  at  a  very  early 
stage,  by  making  a  diagram  at  the  beginning  of  the  work.  Dimen- 
sions of  apparatus,  as  well  as  pipe  lines,  can  be  determined  in  the 
early  stages  of  the  work,  avoiding  the  difficulties  occasioned  by 
altering  specifications  after  the  work  is  let.  It  matters  not  how 
small  the  undertaking  may  be,  the  diagram  will  save  time  in  many 
ways.  If  it  be  at  all  possible,  all  lines  should  be  on  the  one  diagram. 
A  very  practical  method  is  to  use  a  heavy  paper  that  will  stand 
considerable  erasing,  and  lay  out  the  different  lines,  machines,  etc., 
free-hand,  making  the  diagram  on  a  large  sheet  —  say  24  X  36  in. — 
so  that  plenty  of  room  will  be  afforded  for  notes,  dimensions,  etc. 
Whenever  any  changes  are  found  necessary  in  placing  orders  for 
apparatus,  the  diagram  should  be  changed  and  brought  up  to  date. 

This  paper  drawing  is  virtually  a  study,  and  after  details  are 
made  and  the  machinery,  piping,  etc.,  have  been  contracted  for,  a 
smaller  and  neater  diagram  should  be  made  from  it,  one  suitable 
for  permanent  station  use.  The  prints  furnished  the  station  would 
be  better  if  they  were  white  prints  so  as  to  permit  marking  changes 
on  them  in  case  changes  are  made  in  the  station  system.  The 
exhibition  of  diagrams  is  not  customary,  but  if  they  were  prepared 
and  put  on  exhibition,  many  designing  engineers  would  actually  be 
ashamed  of  the  conglomeration  of  pipe  work  that  they  had  designed 
without  employing  even  the  slightest  semblance  of  system. 

It  is  but  just  that  the  purchaser  should  know  what  his  general 
station  system  is  to  be,  and  he  should  demand  a  diagram  and 
learn  what  he  is  receiving.  If  the  system  is  not  provided  for  at 
the  very  inception  of  the  work  there  is  but  little  chance  to  provide  a 


PIPING  DIAGRAMS.  9 

system  after  the  machinery  has  been  ordered.  The  old  saying  "  any 
system  is  better  than  no  system,"  holds  in  station  design  and  the 
conditions  of  service  will  have  to  determine  which  system  is  to  be 
employed.  The  most  complete  and  perfect  system  is  required  for 
stations  that  are  continuously  in  service,  requiring  a  large  portion  of 
their  equipment  to  be  in  operation  at  all  times.  This  system  is 
shown  in  Fig.  i,  and  is  virtually  composed  of  numerous  stations, 
each  complete  in  itself,  and  means  for  connecting  them  into  a  col- 
lective plant  when  desired.  This  is  the  only  system  that  will 
permit  repairs  or  shutdown  of  any  portion  of  the  plant  and  at  the 
same  time  permit  full  operation  of  the  major  portion  of  it.  The 
connecting  mains  are  merely  conveniences,  and  whenever  desired 
can  be  entirely  shut  off  from  the  operating  machines,  allowing  each 
sectional  part  of  the  plant  to  be  operated  independently  of  the 
remainder.  For  instance,  if  the  steam  header  be  shut  off  and  out 
of  use,  the  four  or  more  units  would  be  separately  operated  and 
would  have  different  steam  pressures.  The  steam  from  one  group 
of  boilers  would  then  be  used  in  its  companion  engine  only.  This 
system  is  somewhat  expensive,  requires  more  room  for  lines  than 
a  less  complete  system  and  necessitates  the  arrangement  of 
machines  in  station  groups;  in  fact,  the  grouping  of  the  related 
machines  is  necessary  for  virtually  all  systems,  rather  than  the 
grouping  of  similar  machines.  For  example,  if  a  plant  is  laid  out 
with  engines  in  one  group  and  then  a  group  of  pumps,  then  a 
group  of  economizers  and  then  a  group  of  boilers,  we  can  rest 
assured  that  but  little  system  in  pipe  work  can  be  employed. 

As  stated  before,  in  order  to  establish  a  system  in  station  design 
it  must  be  done  before  any  machinery  is  ordered.  There  are  vari- 
ous systems  to  employ  in  station  designing,  each  suitable  for  a 
particular  line  of  service.  The  more  flexible  system  is  likewise  the 
more  expensive  to  construct  and  maintain;  it  requires  a  much 
more  intelligent  operator  and  necessitates  many  cross  connections 
that  frequently  bring  in  difficulties  in  regard  to  expansion  and 
contraction.  This,  however,  must  be  given  proper  consideration 
and  determined  by  competent  pipe  work  engineers,  as  it  is  often  the 
case  that  the  cross  connections  occasion  more  difficulties  and  shut- 
downs than  would  the  machine  for  which  cross  connections  have 
been  provided. 

Fig.  2  shows  a  divided  station,  necessitating  the  use  of  certain  sec- 
tions of  mains  in  order  to  operate  the  plant.  With  this  system,  a 


IO 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


FIG.  i.   Diagram  of  Unit  System  Plant. 


PIPING  DIAGRAMS, 


II 


12  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

station  of,  say  six  units,  may  be  divided  into  three  distinct  parts, 
each  operative  throughout  and  wholly  independent  of  the  others. 
This  system  costs  much  less  than  No.  i  and  requires  but  two  auxil- 
iaries of  each  kind  for  the  entire  plant.  This  system  is  suitable 
only  for  such  installations  as  are  worked  on  less  than  full  load  for 
sufficient  time  to  make  any  necessary  repairs  to  the  mains.  A 
plant  that  has  half  of  its  installation  idle,  say  for  six  hours  a  day, 
can  be  divided  into  two  sections  instead  of  six,  as  shown,  and  the 
necessary  repairs  to  mains  be  made  at  times  of  light  load  by 
using  one-half  of  the  plant.  If  the  plant  requires  two-thirds  of 
its  installation  for  its  lightest  loads,  then  it  would  be  necessary  to 
divide  the  station  into  three  sections.  The  machinery  should  be 
ordered  to  suit  these  conditions;  instead  of  using  four  engines  and 
eight  boilers,  there  should  be  three  engines  and  nine  boilers, 
allowing  the  boilers  to  be  of  relatively  larger  capacity  than  the 
engines,  so  that  while  working  under  ordinary  conditions,  one 
boiler  can  be  off  and  the  others  handle  all  the  engines.  Each 
heater,  feed  pump,  etc.,  should  be  able  to  handle  the  requirements 
of  the  entire  plant,  even  though  it  be  necessary  to  slightly  crowd 
it  if  the  plant  is  in  full  operation.  In  case  of  shutting  off  a  middle 
section  both  ends  would  be  separately  operated.  This  system  is 
suitable  for  installations  that  will  permit  repairs  to  be  made  to 
the  mains  during  the  time  of  light  load.  If  the  mains  be  extremely 
heavy  or  require  much  time  for  repairs  to  be  made,  system  No.  i 
is  imperative,  for  with  that  system  the  mains  may  be  out  of  service 
for  weeks  at  a  time  and  not  necessarily  interfere  with  ordinary 
service. 

There  is  another  system  which  can  be  employed,  necessitating 
the  use  of  much  more  piping  and  resulting  in  increased  cost  of 
installation,  operation  and  maintenance.  This  is  shown  in  Fig.  3. 
Property  conditions  may  demand  such  a  layout.  This  system  is  the 
loop  system  and  it  will  permit  shutting  off  any  portion  of  the  mains 
and  only  necessitates  shutting  down  one-third  of  the  plant.  This 
system  requires  about  four  times  the  length  of  steam  main  required 
for  system  No.  i.  The  size  of  the  mains  must  also  be,  if  anything, 
slightly  larger.  In  system  No.  i  there  is  no  point  in  the  steam 
main  where  one-half  the  output  of  plant  will  pass.  In  system  No.  3 
either  side  of  the  loop  may  be  compelled  to  carry  two-thirds  of  the 
output  of  station  in  case  a  portion  of  the  main  is  shut  down.  This 
system  has  many  objections,  but  it  is  far  preferable  to  a  double 


PIPING  DIAGRAMS. 


main  system  as  shown  in  Fig.  4.  The  double  main  system  necessi- 
tates tying  from  each  piece  of  apparatus  to  two  different  mains, 
and,  due  to  the  fact  that  one  main  would  be  expanded  and  the  other 
contracted,  severe  strains  are  thrown  on  joints  unless  both  mains 


Main 


FIG.  3.   Diagram  of  Loop  System  Plant. 

be  kept  a  sufficient  distance  away  from  their  connections.  Each 
main  would  of  necessity  be  compelled  to  carry  not  less  than  two- 
thirds  the  output  of  the  plant,  if  arranged  as  in  Fig.  4. 

Fig.  5  shows  such  a  crude  method  of  piping  a  plant  that  it  is 
hardly  worthy  of  being  called  a  system.     In  case  of  repairs  to  the 


-feed 


mill 


FIG.  4.     Diagram  of  Double  Main  System  Plant. 

mains  the  plant  must  be  completely  shut  down  while  they  are 
being  made.  Generally,  difficulties  can  be  anticipated  in  a  failing 
line,  and  repairs  arranged  before  a  shutdown  becomes  necessary. 
If  it  is  imperative  that  there  be  no  shutdowns  during  the  regular 
run,  the  connections  as  shown  in  Fig.  5  should  not  be  considered. 
To  avoid  this  system  and  at  the  same  time  not  be  compelled  to 
make  a  big  investment  in  piping,  the  plant  should  be  laid  out  so 


14  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

system  No.  2  may  be  used,  this  system  giving  by  far  the  greatest 
protection  for  the  least  money.  Unfortunately,  we  will  find  system 
No.  5  partially  used  in  the  same  stations  that  are  using  some 
of  the  other  systems.  There  is  no  reasonable  excuse  for  laying 
out  main  steam  lines  according  to  systems  No.  2,  3  or  4  and  con- 
necting up  boiler  feeds  or  other  vital  lines  on  system  No.  5. 


1 


_L 


FIG.  5.   Diagram  of  Systemless  Plant. 

A  piping  layout  cannot  be  called  a  systematic  arrangement  if  it 
lacks  consistency.  It  is  purely  a  waste  of  money  to  guard  heavy 
steam  and  exhaust  mains  against  almost  any  contingency  and  then 
use  System  No.  5  to  supply  engines  with  oil,  etc.  The  station  is 
not  correctly  laid  out  if  all  the  absolutely  essential  lines  are  not 
laid  out  on  same  or  a  similar  basis.  For  example,  if  it  is  laid  out 
on  system  No.  2  the  operator  should  find  it  possible  to  shut  off  any 
piece  of  piping  or  underground  work  and  make  repairs,  and  not 
shut  down  more  than  one-sixth  of  the  plant;  if  on  system  No.  3, 
he  should  not  shut  down  more  than  one-fourth  of  the  plant  using 
four  units.  Feed  mains,  blow-off  lines,  pump  suctions,  oil  drips, 
etc.,  should  all  be  comprised  in  the  system.  The  condenser, 
heater  and  economizer  connections  can  be  looked  upon  as  second- 
aries and  the  connections  to  them  may  be  on  system  No.  2,  even 
though  the  main  lines  are  on  system  No.  i. 

The  object  of  station  system  is  to  insure  continuous  operation. 
The  condenser,  heater  and  economizer  are  not  absolutely  essential, 
and  the  same  amount  of  refinement  is  not  necessary  with  these 
devices,  which  are  virtually  station  economies,  not  operating 
necessities.  However,  their  importance  must  not  be  under- 
estimated, and  fair  protection  should  be  given  them  by  the  systems 
according  to  which  they  are  connected.  To  operate  without 
these  auxiliaries  is  possible,  but  very  undesirable.  One  condenser 


PIPING  DIAGRAMS.  15 

doing  the  work  of  two  and  giving  but  10  or  15  inches  vacuum  is 
far  preferable  to  exhausting  to  the  atmosphere  with  the  attendant 
engine  difficulties.  One  heater  doing  the  work  of  two  and  delivering 
water  to  the  boilers  at  but  125°  F.  is  far  preferable  to  feeding  cold 
water.  These  considerations  are  covered  by  system  No.  2.  The 
condensers,  heaters,  economizers  and  pumps  would  be  suitable 
for  four  units  and  capable  of  supplying  all  six  under  reduced 
economy.  This  enables  repairs  at  any  time  of  any  auxiliary 
without  interfering  with  the  operation  of  the  plant.  The  main 
steam  header  and  feed  mains  are  divided  into  six  sections,  per- 
mitting the  use  of  five-sixths  of  the  entire  plant  at  all  times. 

In  formulating  the  plans  for  a  station  it  is  well  to  bear  in  mind 
the  path  of  flow  of  steam  and  exhaust.  The  boiler  can  be  consid- 
ered the  starting  point  of  the  loop  and  the  engine  the  terminal.  The 
pumps,  heaters,  condensers  and  pipe  lines  lie  between.  To 
simplify  the  piping  plans  it  is  very  essential  that  the  auxiliaries 
be  located  in  close  proximity  to  the  main  units.  The  diagrams 
show  them  at  considerable  distances  apart,  but  this  is  merely 
to  make  the  system  readily  understood  and  to  leave  ample 
room  to  make  alterations  on  the  diagram  if  found  necessary. 

In  addition  to  the  plan  diagrams,  there  should  be  an  elevation 
diagram,  laid  out  to  scale  for  elevation  only,  as  shown  in  Fig.  6. 
This  elevation  diagram  is  a  portion  of  the  station  system  and 
should  be  determined  if  piping  is  to  be  figured  on  from  the  diagrams 
and  building  drawings.  It  shows  the  various  elevations  of  lines, 
lifts  of  pumps,  drains  for  steam,  exhaust  and  oil  lines  and  other 
points  that  must  not  be  lost  sight  of  in  the  designing  of  pipe  details. 
For  example,  it  shows  that  auxiliary  exhaust  main  must  not  be 
lowered  very  much  or  it  will  not  drain  to  the  heater.  It  also 
shows  how  much  fall  is  given  the  pump  suction  from  the  heater 
and  other  details  that  should  be  considered  and  laid  out  by  the 
engineer  in  order  to  locate  the  apparatus  correctly.  It  is  not 
necessary  to  show  all  the  boilers  or  branches,  but  simply  the  lines 
that  must  be  located  in  some  fixed  relation  to  each  other.  The 
location  of  lines  should  be  left  to  the  detailer  and  only  interferences 
should  be  shown  or  noted. 

Diagrams  prepared  as  here  shown  are  excellent  means  of  study- 
ing station  work.  The  different  lines  can  be  separately  laid  out 
and  they  make  good  studies.  Take,  for  example,  Fig.  7.  This  dia- 
gram shows  a  boiler  feed  system,  which  is  a  loop  system  as  regards 


16 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


PIPING  DIAGRAMS. 


FIG.  7.   Diagram  Study. 


18  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

boiler  feeding,  but  in  actual  service  the  loops  are  divided,  part 
being  used  for  a  secondary  service,  such  as  a  hydraulic  line  for  tube 
cleaning  or  low  pressure  general  water  service  for  the  station.  In 
case  it  becomes  necessary  to  shut  down  the  left  hand  portion  of  the 
regular  feed  line,  from  valves  A  to  B,  then  it  becomes  necessary  to 
use  the  right  hand  portion  and  deliver  water  to  No.  2  feed  pump. 
If  found  desirable,  valve  C  may  be  shut  and  pump  can  take  water 
direct  from  the  intake  through  valve  D.  Under  all  ordinary 
conditions  the  hose  line  in  front  of  the  boilers  would  be  under  low 
pressure,  about  50  lb.,  but  if  valves  E  and  F  must  be  closed  the 
hose  line  may  be  used  as  part  of  the  feed  system  to  supply  boilers 
No.  i  and  2.  In  case  of  fire,  the  by -pass  valves  G,  H,  S  and  K  may 
be  opened  and  L  and  M  closed,  thus  putting  the  entire  low  pressure 
system  under  high  pressure.  This  diagram  shows  a  rather  unusual 
method  of  feeding  boilers.  Water  is  taken  from  the  hot  well  by 
means  of  motor  driven  centrifugal  pumps  and  discharged  under 
say  50  lb.  pressure  through  the  closed  heater  and  economizer  to 
the  suction  of  the  feed  pumps.  The  feed  pumps  would  be  con- 
trolled by  hand  or  automatically  to  supply  the  boilers,  the  suction 
being  maintained  under  50  lb.  pressure  by  the  centrifugal  pumps. 
If  at  any  time  both  centrifugal  pumps  are  out  of  service,  then  the 
feed  pumps  would  take  their  suction  direct  from  the  intake.  The 
advantage  of  this  system  lies  in  the  fact  that  the  heater  and  econ- 
omizers are  never  subjected  to  high  pressure  such  as  boilers  would 
be.  Instead  of  the  economizers  being  a  constant  source  of  trouble, 
they  will  operate  in  their  old-time  reliable  and  satisfactory  manner, 
on  extremely  low  pressure  as  compared  with  those  economizers 
which  are  placed  between  boilers  and  pumps  and  subjected  to  care- 
less abuse  of  firemen,  such  as  closing  all  feed  valves  and  allowing 
feed  pumps  to  pound  away  on  them.  The  centrifugal  pumps 
would  maintain  a  uniform  pressure  and  not  require  a  relief  other 
than  a  small  one  that  would  relieve  the  pressure  in  case  the  valves 
are  shut  both  sides  of  the  economizers  and  the  rise  in  temperature 
of  the  water  in  the  economizers  should  cause  increase  of  pressure. 
The  pressure  in  economizers  must  be  sufficient  to  avoid  generation 
of  steam.  There  are,  however,  many  low  pressure  installations 
using  economizers,  and  the  aim  should  be  to  use  as  low  a  pressure 
as  is  found  practicable.  It  would  also  be  advisable  to  place  econ- 
omizers sufficiently  above  the  feed  pumps  to  permit  the  suction  to 
flow  by  gravity  to  the  pumps. 


PIPING   DIAGRAMS.  19 

The  chief  object  in  showing  this  unusual  system  is  to  call  to  the 
attention  of  the  reader  how  readily  the  complex  problems  of  station 
design  can  be  laid  out  and  made  perfectly  clear  without  resorting 
to  scale  drawings.  No  station  work  can  be  laid  out  even  in  a 
preliminary  way  until  the  system  of  connecting  up  is  determined. 
It  is  very  much  to  be  regretted  that  the  periodicals  show  general 
views  of  the  new  power  plants  and  fail  to  show  the  system  that 
determined  the  arrangement  of  the  plant.  Not  only  should  the 
piping  system  be  shown,  but  smoke  flues,  stacks,  coal  and  ash 
systems.  The  object  to  attain  is  the  use  of  as  little  machinery  and 
piping  as  possible,  and  at  the  same  time  to  permit  shutting  down 
any  portion  of  the  different  apparatus  and  piping  without  inter- 
fering with  the  service  for  which  the  station  is  intended.  To 
accomplish  this,  it  is  necessary  to  lay  out  the  system  first,  then 
build  the  plant  around  it.  Each  of  the  various  details  must  be 
separately  considered  and  a  careful  determination  made  of  its 
suitability  for  the  purpose  for  which  it  is  intended. 


CHAPTER   III. 
PIPING    SYSTEMS. 

IN  this  chapter  we  consider  the  different  systems  of  connecting 
up  machinery  and  the  various  systems  are  separately  shown  by 
diagrams,  this  method  being  the  most  convenient  one  for  studying 
and  determining  the  requirements  for  each  class  of  service.  The 
form  in  which  these  different  systems  are  shown  would  ordinarily 
be  the  form  used  for  "studies"  previous  to  laying  out  the  complete 
station  diagram.  The  separate  diagrams  would  be  somewhat  more 
distinct  than  a  general  diagram  of  all  the  lines,  but  the  former 
would  not  serve  to  call  to  the  attention  of  the  pipe  work  designer 
and  erector  such  other  lines  as  come  in  close  proximity,  and  for 
which  provision  must  be  made.  The  general  diagram  of  all  the 
lines  on  the  same  sheet,  each  in  approximately  its  correct  position, 
acts  as  a  constant  reminder  and  greatly  reduces  the  labor  of 
laying  out  lines  as  well  as  the  possibility  of  overlooking  some  of 
them.  This  is  the  kind  of  drawing  that  should  be  furnished  to  the 
piping  contractor,  showing  the  desired  results  but  permitting  him  to 
lay  out  the  details  so  as  to  accomplish  these  results  in  the  simplest 
and  most  economical  manner. 

In  case  the  contractor  should  fail  to  provide  for  any  lines  shown 
on  this  diagram  he  would  necessarily  be  obliged  to  make  changes 
so  that  the  work  would  conform  to  the  diagram,  and  as  such 
changes  would  be  due  to  an  oversight  on  his  part  he  could  make  no 
charge  for  them.  The  common  practice,  however,  is  to  detail  a 
portion  of  the  work,  leaving  the  uncertain  and  indefinite  features 
to  be  covered  by  some  general  clause  in  the  contract  which  protects 
neither  the  purchaser  nor  the  contractor,  but  which  merely  leaves  a 
loop  hole  for  the  engineer  to  shift  the  responsibility  upon  the 
purchaser  or  the  contractor.  Contractors,  however,  can  protect 
themselves  by  adding  the  following  clause  to  all  quotations : 

"This  proposal  covers  only  such  materials  as  are  definitely  shown 
or  listed  on  drawings  or  in  specifications." 

Contractors  are  not  at  the  mercy  of  engineers  when  it  comes  to 

20 


PIPING   SYSTEMS. 


21 


making  bids.  When  an  engineer  has  certain  work  to  do  he  is 
compelled  to  place  an  order  for  it.  If  he  cannot  place  the  order 
on  his  own  terms  he  must  accept  the  contractor's  terms.  If  he 
ignores  all  of  the  contractors  who  use  this  clause  in  their  bids  they 
can  notify  the  purchaser  to  this  effect,  and  as  the  purchaser  is 
invariably  a  business  man,  he  will  readily  appreciate  the  fairness 
of  such  a  clause.  The  result  would  be  that  the  engineer  would 
be  careful  to  make  a  study  of  the  requirements  instead  of  spending 
his  time  in  the  study  of  pipe  work  details.  He  would  lay  out  a 
diagram  of  every  line  and  system  required,  make  the  contractor 
familiar  with  the  situation  and  make  him  responsible  for  the 


-t"- 


: 


f 

r 

a< 

f 

• 

r 

f, 

B 

1  ft/rf^S 

1 

1 

e. 

1 

#3 

1 

1 

FIG.  8.   System,  Steam  and  Feed,  One  Division  Plant. 

design,  details,  location  and  the  support  of  all  lines.  The  con- 
tractor would  look  after  his  clearances  and  would  take  nothing  for 
granted  as  he  would  have  to  do  if  the  engineer  furnished  the 
working  drawings. 

The  various  systems  are  described  in  a  general  way  and  later  on 
the  parts  of  each  system  are  considered  in  detail.  Fig.  8  shows  the 
plan  of  a  station  having  three  generators  and  five  boilers  at  one  end 
of  the  station  and  the  exciters  and  pumps  at  the  other  end.  The 
dotted  lines  indicate  future  extensions.  This  plan  will  not  appeal 
to  the  reader  as  unusual  for  he  probably  has  in  mind  several 
stations  similarly  arranged.  Generally  it  may  be  assumed  that 
the  piping  and  machinery  should  be  laid  out  as'shown,  but  instead 
of  using  the  piping  arrangement  given  in  Fig.  8  it  may  be  desirable 
to  employ  some  system; -that  is,  some  arrangement  that  will  pro- 
vide for  continuous  operation  of  the  plant  and  by  means  of  which 
at  least  two-thirds  of  the  plant  may  remain  in  operation  during  the 


22 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


tinu-  that  repairs  are  being  made.  Fig.  9  shows  the  pipe  work  of 
this  station  redesigned  so  as  to  conform  to  such  a  system.  It  may 
be  noted  that  two  generators  out  of  the  three,  three  boilers  out  of 
the  five,  also  one  feed  pump  and  one  exciter  engine  can  be  used 
at  any  time,  thus- permitting  the  shutting  down  of  any  portion  of 
the  steam  main  which  may  need  repairs.  The  value  of  laying  out 


r 


FIG.  9.   System,  Fig.  8  Modified  to  Multiple  Division  Plant. 

a  diagram  before  ordering  the  machinery  shows  itself  clearly  when 
considering  whether  a  better  system  could  be  laid  out.  Fig.  10 
shows  a  better  balanced  system  in  which  there  are  no  double  lines 
of  piping,  and  this  arrangement  allows  the  use  of  two  boilers  for 
each  of  the  two  engines  in  case  repairs  are  being  made. 

To  lay  out  a  station  system  requires  full  consideration  of  a  great 
many  details  besides  piping,  but  these  details  must  be  considered 
as  only  a  part  of  the  system  and  nothing  pertaining  to  the  station 
should  be  ordered,  or  even  considered  as  final,  until  all  of  the 
details  of  the  system  have  been  thoroughly  digested  and  determined. 
It  is  very  easy  to  refer  to  the  diagram  in  Fig.  8  and  say  that  it 
should  have  been  arranged  as  in  Fig.  10,  although  the  conditions 
may  have  been  such  that  the  arrangement  shown  in  Fig.  9  might 
be  the  best  solution  with  possibly  a  change  in  the  number  of  boiler 
units.  No  plan  or  system  can  be  styled  a  priori  the  "best,"  for 
that  one  is  the  best  in  each  case  which  best  complies  with  all  of 
the  conditions.  Nevertheless  a  fixed  plan  for  securing  the  most 
satisfactory  results  can  be  followed  and  no  matter  what  the  sur- 
rounding conditions  are,  some  system  can  be  employed. 

The  fundamental  requirements  of  station  systems  are  reliability, 


PIPING  SYSTEMS. 


accessibility  and  durability.  The  requirements  of  the  station  must 
be  first  determined  and  some  system  adopted  that  will  meet  these 
requirements.  If  the  requirements  are  that  the  station  should  run 
as  many  hours  a  day  as  is  convenient  for  the  station  operators,  the 
system  for  such  a  condition  needs  practically  no  valves,  no  reserve 
capacity  nor  any  emergency  provisions.  However,  this  class  of 
station  work  does  not  come  into  the  hands  of  an  engineer  to  lay 
out.  He  is  engaged  to  design  stations  that  will  never  require  a 
shutdown  of  the  entire  system.  It  is  the  conditions  of  service  that 


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FIG.  10.    Sample  System;  Steam  and  Water,  3  to  4  Division  Plant. 

must  determine  the  system.  If  the  service  is  twenty  hours  a  day 
the  station  should  be  laid  out  with  this  in  view.  If  it  must  run 
twenty-four  hours  a  day,  running  for  eight  hours  at  half  load 
only,  then  the  system  should  provide  for  repairs  being  made  and  at 
the  same  time  maintaining  the  capacity. 

The  method  of  determining  the  most  suitable  size  of  units  for 
a  station  will  not  be  considered  in  detail  as  the  question  is  quite 
foreign  to  piping  and  piping  systems  except  in  so  far  as  the  number 
of  units  is  concerned;  if  the  station  is  required  to  generate  at  all 
times  two-thirds  of  its  total  capacity  the  plant  should  not  have  less 
than  three  units  all  of  the  same  size.  No  unit  should  be  so  large 
that  the  station  cannot  be  operated  without  it  by  overloading  the 
other  machinery  to  the  permissible  limit.  The  practical  advan- 
tages in  having  units  of  the  same  size  and  pattern  are  too  great 
to  be  abandoned  on  account  of  the  petty  economies  that  may  be 
secured  under  certain  conditions  by  using  one  large  unit.  As  an 
illustration  of  this  the  following  case  of  a  breakdown  is  instruc- 
tive. Three  units  were  installed,  all  of  the  same  kind,  size  and 


24  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

pattern.  One  unit  was  out  of  sen-ice,  the  crank  pin  boxes  having 
been  removed  for  rcbabbitting,  fitting,  etc.  Two  engines  were 
required  to  carry  the  load,  and  while  this  engine  was  out  of  service, 
a  valve  eccentric  rod  broke,  which  necessitated  running  one  engine 
with  almost  a  double  load.  The  valve  rod  was  immediately  taken 
from  the  engine  out  of  service  and  fitted  to  the  engine  that  broke 
down,  so  that  in  a  short  time  the  latter  was  in  service  again.  The 
single  engine  could  not  have  carried  this  overload  except  for  a 
very  short  time,  and  having  all  the  engines  of  the  same  pattern 
avoided  a  shutdown.  If  the  engines  had  not  been  all  similar  the 
plant  would  have  had  to  be  shut  down  at  least  a  day  in  order  to 
finish  the  repairs. 

In  any  case  the  original  installation  should  be  for  a  two-division, 
three -division  or  four-division  plant  with  provision  for  future 
divisions.  If  the  plant  is  to  be  a  two-division  plant  it  may  be  built 
with  two  units,  each  of  a  capacity  slightly  larger  than  the  minimum 
load  conditions  demand,  and  the  future  unit  may  be  made  twice  the 
capacity  of  these  smaller  units.  This  arrangement  of  units  would 
be  permissible  in  a  plant  which  ordinarily  delivers  only  half  of  the 
power  called  for  on  Sundays,  holidays,  etc.,  and  this  condition  is 
quite  an  unusual  one  in  power  stations.  It  has  been  found  ordi- 
narily that  a  three-division  plant  is  more  suitable  for  permitting 
repairs  to  be  made  and  also  requires  less  investment  for  reserve 
capacity.  If  the  plant  is  to  be  a  three-division  plant,  the  boilers 
should  be  in  three  divisions,  say  six,  nine  or  twelve  in  number. 
The  auxiliaries  should  be  in  pairs,  not  necessarily  together,  but 
each  sufficient  for  the  entire  plant,  and  they  should  be  connected 
to  the  different  divisions  so  that  when  one  division  is  out  of  ser- 
vice the  other  auxiliary  will  be  on  an  operating  division. 

In  order  to  more  fully  explain  the  features  to  be  determined  by 
diagrams  as  well  as  the  laying  out  of  the  diagram  the  requirement 
of  a  sample  station  will  be  considered  and  the  method  of  select- 
ing machinery,  etc.,  followed  up.  It  will  also  be  shown  that  by 
this  method  can  be  determined  much  of  the  station  layout  and 
the  auxiliaries  required  at  the  same  time  the  piping  system  is 
developed. 

Let  it  be  assumed  that  the  station  will  now  require  three  units 
for  an  output  of  two-thirds  of  the  total  capacity  of  the  units  and 
later  will  require  an  additional  unit  such  as  shown  in  the  diagram 
Fig.  10.  There  is  but  one  solution  of  the  problem  under  these 


-<    PIPING   SYSTEMS.  2$ 

conditions,  and  that  is  that  the  station  shall  ultimately  be  a  four- 
unit  plant  for  output  of  three-quarters  of  the  total  capacity  of  the 
units.  The  boilers  must  be  arranged  in  three  units  so  as  to  allow 
one  to  be  out  of  condition  for  cleaning  and  repairs.  Boiler  clean- 
ing must  not  be  considered  a  contingency  but  a  requirement  that  is 
certainly  unavoidable. 

Assuming  the  engines  to  be  of  2,000  hp.  each,  then  two  5oo-hp. 
boilers  would  be  required  for  each  engine,  but  by  assuming  three 
engines  of  2,000  hp.  each  or  a  total  of  6,000  hp.,  there  would  be 
3,000  hp.  in  boilers  to  be  divided  into  five  units,  so  as  to  allow  one 
boiler  to  be  out  of  service.  This  would  give  five  6oo-hp.  boilers. 
If  the  fourth  engine  unit  is  likely  to  be  ordered  before  the  three 
units  are  called  upon  to  carry  full  load  for  a  large  part  of  the 
time  it  would  be  safe  to  estimate  on  8,000  hp.  of  engines  or  4,000 
hp.  of  boilers  or  seven  boilers,  each  of  555  hp.,  which  is  a  some- 
what better  arrangement  for  the  four-unit  plant. 

When  it  comes  to  determining  auxiliaries  there  should  be  con- 
sidered only  that  future  unit  for  which  space  has  been  provided  in 
the  building.  More  than  this  is  useless  speculation,  and  further, 
such  apparatus  as  would  be  provided  to-day,  it  is  possible  that  no  one 
would  think  of  using  in  the  future  when  it  came  to  be  required. 
The  present  installation  may  include  one  of  the  two  condensers 
for  the  completed  plant,  in  which  case  it  would  be  advisable  to 
provide  a  5,ooo-hp.  condenser  which  would  be  larger  than  re- 
quired for  two  units,  but  somewhat  small  for  the  three  units.  A 
loss  in  vacuum  would  be  so  infrequent  that  its  effect  on  the  station 
economy  would  be  imperceptible.  If  the  fourth  unit  is  to  be  in- 
stalled at  an  early  date  it  would  then  be  more  economical  to  put 
in  two  condensers  at  the  time  the  three  units  were  installed.  These 
are  points  that  the  engineer  must  determine,  and  he  may  decide 
that  he  would  not  wish  the  plant  to  run  non-condensing  even  dur- 
ing the  short  time  required  to  make  a  repair.  As  this  would  be  the 
case  if  one  condenser  were  installed,  it  is  assumed  that  two  are 
wanted. 

The  atmospheric  exhausts  must  be  so  designed  that  a  repair  to 
one  must  not  interfere  with  the  others,  as  the  atmospheric  exhaust 
is  one  of  the  vital  lines  of  the  plant  and  must  be  as  well  safe- 
guarded as  the  steam  header.  Assume  that  the  condensers  will  be 
of  the  elevated  jet  type,  with  electrically  driven  centrifugal  circulat- 
ing pumps.  Economizers  will  be  installed,  and  as  no  steam  will 


26 


STEAM    POWER   PLANT  PIPING  SYSTEMS. 


PIPING   SYSTEMS.  2J 

be  required  to  heat  the  feed  water,  the  installation  can  be  simplified 
by  using  motor  driven  circulating  pumps  instead  of  engine  driven. 
In  case  the  lift  be  slight,  engine  driven  circulating  pumps  may  be 
used  and  the  exhaust  carried  to  the  heater,  but  the  engines  ordi- 
narily used  for  this  service  are  so  uneconomical  in  steam  con- 
sumption that  together  with  the  other  auxiliaries  they  would 
deliver  more  exhaust  steam  than  the  heater  could  condense.  The 
difference  in  economy  between  engines  exhausting  part  of  their 
steam  to  the  atmosphere  and  electrically  driven  pumps  is  so  slight 
that  the  better  practice  is  to  adopt  that  which  requires  the  least 
labor  to  operate,  which  is  unquestionably  the  motor  drive.  One, 
two,  three  or  four  circulating  pumps  can  be  used  for  the  two  con- 
densers and  only  such  as  are  required  to  deliver  the  necessary 
cooling  water  be  operated.  It  may  be  assumed  for  the  present 
that  three  circulating  pumps  will  be  used,  each  sufficient  for  one 
condenser,  although  when  the  circulating  water  is  extremely  hot 
all  three  pumps  may  be  required  for  the  two  condensers. 

The  requirements  to  be  met  by  the  dry  vacuum  pump  are  so 
variable,  due  to  changes  in  the  temperature  of  the  water,  amount 
of  vegetable  matter  it  contains  and  the  air  leaks  in  the  pipe  line, 
that  it  may  be  necessary  to  run  the  air  pump  at  a  very  high  speed 
some  days,  and  possibly  it  can  be  run  very  slowly  a  week  later. 
Any  motor  drive  is  very  unsatisfactory  for  the  air  pump,  so  it  will 
be  considered  that  this  will  be  of  the  steam  driven  fly-wheel  type. 
It  is  possible  to  vary  the  speed  of  the  dry  vacuum  pump  over  a 
wide  range,  and  as  it  is  important  to  minimize  the  labor  for  attend- 
ance, one  dry  vacuum  pump  for  both  condensers  will  be  chosen. 

In  regard  to  the  boilers,  they  will  be  taken  to  be  of  the  water 
tube  type  set  two  in  each  battery,  and  in  order  to  include  more 
piping  details  in  the  plan  it  will  be  assumed  that  underfeed  stokers 
are  to  be  used  and  also  induced  fan  draft.  As  previously  stated, 
economizers  will  also  be  used. 

In  order  to  make  the  station  operation  secure  against  all  con- 
tingencies it  may  be  arranged  to  have  each  battery  of  boilers  dis- 
tinct by  itself.  Each  battery  will  have  its  own  economizer,  its 
own  by-pass  flue,  stack  and  fan  engine,  the  same  engine  driving 
both  the  blast  fan  and  stack  fan  with  a  cutting  in  arrangement 
both  for  the  air  blast  and  the  main  flue,  as  shown  in  Fig.  u.  By 
speeding  up  these  engines  two  of  them  should  have  sufficient  capac- 
ity for  three  batteries  of  boilers.  After  a  careful  consideration  it 


28 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


PIPING   SYSTEMS.  2Q 

may  be  decided  to  use  the  plan  shown  in  Fig.  12,  making  the  fan 
engines  capable  of  taking  care  of  three  batteries  of  boilers  each  by 
speeding  them  up.  This  would  make  somewhat  less  machinery 
to  care  for  and  would  allow  either  fan  engine  to  be  shut  down  and 
would  make  it  possible  to  run  all  of  the  present  installation  or  three- 
quarters  of  the  future  installation.  This  would  necessitate  the 
use  of  a  second  fan  engine  and  stack  in  order  to  insure  continuous 
operation  of  the  present  three-unit  installation. 

By  placing  economizers  in  separate  groups  as  shown  it  becomes 
a  very  simple  operation  to  clean  them,  as  this  can  be  done  when 
the  battery  of  boilers  is  out  of  use  and  after  the  brickwork  has 
cooled  down.  It  is  wholly  useless  to  invest  money  in  economizers 
and  not  to  make  most  liberal  provision  for  cleaning  them.  They 
are  sometimes  allowed  to  fill  up  with  deposits  inside  and  outside 
so  that  they  will  not  raise  the  temperature  of  the  water  more  than 
20  to  30  degrees,  while  if  they  are  cleaned  both  inside  and  out  they 
can,  as  proved  in  practice,  raise  the  temperature  of  the  water  from 
50  to  270  degrees,  a  total  of  220  degrees.  In  order  to  cool  the 
economizers  sufficiently  to  permit  careful  and  thorough  cleaning 
no  gases  should  be  allowed  to  pass  on  the  outside  of  any  of  the 
economizer  walls  while  the  cooling  and  cleaning  is  in  progress.  It 
may  occur  to  the  engineer  that  he  can  save  in  space  and  in  first 
cost  of  installation  by  placing  the  main  flue  to  the  stack  between 
the  boiler  and  building  wall  and  place  the  economizer  on  top  of 
this,  boxed  in  so  to  speak,  without  any  possible  chance  to  cool 
them  off.  Where  else  in  the  plant  can  he  save  from  10  to  15  per 
cent  in  the  cost  of  fuel  by  doing  better  engineering?  The  saving 
in  this  detail  alone  will  in  five  years  pay  the  entire  cost  for  engi- 
neering of  the  power  station.  The  cross  connecting  flue  can  be  of 
light  iron  and  left  uncovered,  as  it  is  required  only  in  cases  of 
emergency,  when  one  of  the  fan  engines  is  out  of  service.  The 
radiation  of  heat  would  be  confined  to  the  fan  casing  and  the 
stack.  There  are  many  interesting  details  in  connection  with  the 
boiler  and  economizer  settings,  smoke  flues,  air  pipes,  etc.,  but  as 
they  are  somewhat  foreign  to  the  piping  system  these  details  will 
not  be  further  discussed. 

Assume  that  the  arrangement  shown  in  Fig.  1 2  has  been  adopted 
for  the  station  in  question.  There  are  the  two  fan  engines  to  pro- 
vide for  and  the  piping  system  and  also  the  stoker  rams.  The 
next  question  that  arises  is,  What  shall  be  done  for  boiler  feed 


30  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

pumps  ?  Electrically  driven  feed  pumps  are  not  satisfactory  except 
when  the  motors  can  be  run  within  a  very  limited  range  of  speed. 
If  the  station  were  very  large  four  electrically  driven  pumps  to- 
gether with  a  steam  pump  could  be  used,  the  latter  being  used 
with  any  or  all  of  the  electrically  driven  pumps  to  take  care  of 
any  demand  less  than  the  capacity  of  one  motor  driven  pump;  one 
of  the  electrically  driven  pumps  could  be  shut  down  when  the 
slowing  down  of  the  steam  pump  still  gave  more  water  than  was 
required.  For  a  plant  of  the  size  in  question,  however,  the  addi- 
tional maintenance  of  using  electrically  driven  feed  pumps  is  not 
justified.  There  is  also  needed  a  line  of  pipe  to  which  the  water 
tube  cleaner  turbine  may  be  attached,  and  this  must  be  supplied 
from  some  other  than  the  feed  pump.  This  is  imperative,  for  water 
must  not  be  drawn  from  the  feed  main  for  any  purpose  whatever 
except  to  feed  such  boilers  as  are  under  pressure.  This  require- 
ment must  never  be  lost  sight  of  in  laying  out  a  station  system 
having  an  economizer  or  closed  live  steam  heater  between  the 
pumps  and  the  boilers.  Not  only  should  all  other  service  be  kept 
off  the  feed  main,  but  the  latter  should  at  all  times  be  under  full 
pressure.  The  moment  that  a  hose  line  or  a  connection  into  an 
empty  boiler  is  opened  from  the  feed  line  the  pressure  immediately 
drops  in  proportion  to  the  size  of  the  opening,  possibly  10  or  15  Ib. 
The  temperature  of  the  water  in  a  live  steam  heater  or  an  econ- 
omizer is  sufficiently  high  to  generate  steam  when  the  pressure  is 
lowered,  and  this  causes  a  serious  water  hammer  in  the  economizer, 
heater  or  pipe  lines.  For  the  same  reason  the  blow-off  from  an 
economizer  should  be  handled  according  to  £n  established  method 
which  will  be  mentioned  later.  Broken  economizer  sections  and 
leaky  joints  are  often  the  results  of  mistreatment. 

In  arranging  for  feed  pumps  two  will  be  required  in  any  case, 
and  while  one  is  used  for  boiler  feeding,  the  other  can  be  used  for 
filling  in  boilers,  running  turbines,  etc.  In  addition  to  these  two 
lines  of  water  service  it  will  be  necessary  to  have  a  low  pressure 
system  operating,  say  on  25  Ib.  pressure,  which  can  be  used  for 
cooling  engine  journals,  wetting  down  ashes,  for  the  plumbing 
fixtures,  washing  floors,  for  the  make-up  water,  to  the  open  heater 
and  other  similar  services.  In  addition  to  this  "house  service" 
there  should  be  a  fire  service  system,  the  pump  for  which  should  be 
able  to  maintain  100  Ib.  pressure  running  full  speed.  These  four 
services  must  be  available  at  all  times,  although  it  is  not  necessary 


PIPING  SYSTEMS.  31 

nor  desirable  to  keep  the  fire  service  pressure  on  all  the  time.  The 
house  service  or  low  pressure  lines  may  be  taken  off  the  fire  system, 
using  reducing  valves  and  reliefs,  and  even  if  there  be  a  reducing 
valve  in  the  line  no  loss  in  economy  of  operations  will  be  effected 
as  long  as  the  fire  system  is  under  the  same  pressure,  say  25  Ib. 
Whenever  the  fire  system  pressure  is  raised  the  pressure  reducing 
valve  and  relief  will  protect  the  line  against  any  careless  manipula- 
tion of  valves. 

There  are  then  various  combinations  of  conditions,  all  of  which 
should  be  fully  met  by  the  system  employed.  The  following  are 
the  different  conditions: 

(1)  Feed  main  on, 

Tube  cleaner  main  on  high  pressure, 
House  service  and  fire  main  on  low  service, 
With  pump  on  each  line. 

(2)  Feed  main  on, 

House  service  low  pressure,  cold  water, 

Fire  main  higher  pressure,  for  outside  sprinkling. 

(3)  Feed  main  on, 
House  service  on, 
Two  pumps  in  service. 

(4)  Feed  main  on, 

House  service  on  through  reducing  valves^ 

Fire  main  on  for  fire, 

With  three  pumps  on,  two  for  pumping  into  fire  main. 

(5)  Feed  main  on, 

House  service  on  through  reducing  valve, 
Any  one  of  the  three  pumps  in  service. 

The  third  condition  would  be  the  regular  operating  one,  leaving 
one  pump  in  reserve  at  all  times.  The  boiler  is  so  important  that 
with  three  pumps  in  the  plant  it  would  be  policy  to  arrange  all  of 
them  so  they  could  feed  boilers,  making  it  possible  to  operate  under 
condition  five.  It  is  possible  that  two  of  the  three  pumps  may  be 
out  of  condition  at  the  same  time.  The  two  boiler  feed  pumps 
would  be  of  the  same  pattern  and  size  with  compound  cylinders 
suitable  for  boiler  feeding,  and  they  should  be  outside  packed. 

The  fire  pump  should  be  of  special  pattern  to  fill  its  various 


32  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

duties.  Probably  a  5oo-gallon  pump  would  have  ample  capacity 
for  fire  protection,  and  owing  to  its  high  speed  it  would  necessarily 
be  of  the  regular  piston  type.  The  cylinder  ratios  should  be  such 
that  the  regular  fire  pump  can  be  used  as  a  feed  pump  to  deliver 
a  small  amount  of  water  such  as  would  be  needed  for  boiler 
feeding.  This  pump  would  be  regularly  used  as  a  25-lb.  pressure 
pump  and  in  order  to  economize  steam  it  would  be  necessary 
to  compound  it,  possibly  six  to  one,  and  use  it  as  a  compound 
pump  for  the  low  pressure  work  only.  By  operating  the  port 
changing  slide  valve  the  pump  would  be  immediately  changed  to 
two  high  pressure  cylinders  for  fire  service  or  boiler  feeding. 

In  many  ways  the  gravity  storage  tank  is  very  desirable,  as  it  pro- 
vides a  storage  for  water  while  changing  over  the  pumps  and  it 
also  helps  to  maintain  a  steady  pressure  of  water.  If  gravity 
tank  water  is  to  be  used  for  cooling  engine  journals,  it  will  neces- 
sitate the  use  of  a  much  larger  amount  of  water  than  otherwise 
due  to  the  tank  becoming  heated.  If  the  tank  be  of  metal  and 
located  near  the  roof,  much  trouble  will  be  experienced  from  its 
sweating,  and  in  order  to  avoid  dripping,  it  will  be  necessary  to 
use  a  water-tight  pan  under  it.  In  order  to  maintain  a  steady 
pressure  with  a  small  amount  of  storage,  it  would  be  preferable 
to  use  a  small  closed  expansion  tank  in  the  basement. 

The  three  pumps  would  ordinarily  use  different  water  for  the 
suctions,  the  boiler  feed  pump  using  hot  water  from  the  heater  and 
the  other  pumps  using  cold  water.  The  pumps  must  therefore  have 
their  suctions  so  piped  that  any  one  of  the  three  can  use  the  heater 
water  or  intake  water. 

Before  laying  out  the  piping  for  this  pumping  system  it  is 
necessary  to  consider  what  to  do  in  regard  to  the  heater.  Shall 
one  or  two  heaters  be  used  ?  Before  attempting  to  determine  this 
question,  it  is  necessary  to  consider  how  essential  the  heater  is 
in  securing  continuous  operation.  There  are  condensing  plants 
using  economizers  and  electrically  driven  auxiliaries  that  take  water 
from  the  hot  well  and  feed  directly  into  the  economizers  without 
having  any  heater  at  all.  Now  if  the  economizers  can  operate 
continuously  without  a  heater,  why  must  we  provide  a  reserve 
heater  for  the  two  hours  or  so  that  it  takes  to  clean  them  out? 
The  only  directly  appreciable  loss  is  the  heat  discharged  from 
the  exhaust  pipe  while  cleaning;  this  is  a  very  insignificant  loss 
considering  the  long  intervals  between  cleanings.  Another  ques- 


PIPING   SYSTEMS.  33 

tion  in  connection  with  the  use  of  two  heaters  is  how  to  take  a 
uniform  amount  of  water  from  each  heater  when  using  one  feed 
pump.  This  can  be  arranged  by  means  of  floats  and  other  un- 
reliable devices,  but  there  does  not  appear  to  be  any  practicable 
method  except  by  the  use  of  two  feed  pumps  working  separately, 
each  with  a  separate  heater.  This  detail  should  not  be  lost  sight 
of  in  determining  the  heaters. 

There  must  also  be  considered  whether  a  closed  or  an  open 
heater  shall  be  used.  The  only  advantage  of  the  closed  heater 
is  that  the  oil  in  the  exhaust  steam  does  not  mingle  in  any  way 
with  the  feed  water.  But  is  this  sufficient  to  outweigh  the  ad- 
vantages of  an  open  heater  for  the  service  in  question?  In  the 
first  place,  the  open  heater  is  made  of  cast  iron  instead  of  plate 
steel,  making  it  able  to  stand  the  chemical  action  within  it  for 
a  longer  time.  Another  feature  of  the  open  heater  is  that  it  is 
not  subjected  to  severe  stresses,  due  to  the  boiler  pressure,  as  is  the 
case  with  a  closed  heater.  The  closed  heater  is  far  more  difficult 
to  clean  and,  in  case  of  a  condensing  plant,  but  little  benefit  would 
be  derived  from  it,  as  the  closed  heater  would  raise  the  temperature 
of  the  water  only  about  one-quarter  as  much  as  the  open  heater. 
If  sufficient  exhaust  steam  is  delivered  to  an  open  heater  to  raise 
the  temperature  of  the  water  75  degrees,  the  same  amount  in  a 
closed  heater  would  raise  it  only  about  17  degrees,  correspond- 
ing to  a  loss  of  nearly  6  per  cent  of  the  coal  consumption.  For 
a  non-condensing  plant  the  closed  heater  deserves  careful  con- 
sideration, but  it  is  quite  out  of  the  question  for  a  condensing 
plant,  as  the  only  exhaust  steam  available  for  the  heaters  is  that 
from  the  auxiliaries.  The  open  heater  should  be  amply  large,  not 
so  much  for  the  purposes  of  a  heater,  but  to  permit  possible  chemi- 
cal treatment,  precipitation,  and  to  provide  a  large  filter  bed.  There- 
fore one  open  heater  is  chosen  for  the  station  under  consideration. 

There  are  other  features  still  to  be  considered  before  laying  out 
the  pump  piping.  Shall  a  water  meter  be  used,  and  if  so,  where 
shall  it  be  located  ?  Also  how  shall  water  be  taken  from  the  hot 
well  and  delivered  to  the  heater  ?  Water  could  be  supplied  to  the 
heater  by  the  fire  pump  while  it  is  being  used  on  the  house  service, 
but,  by  doing  this,  water  would  be  delivered  to  the  heater  from  the 
intake  at  possibly  60  degrees  instead  of  90  degrees,  a  loss  of 
30  degrees.  If  using  90  tons  of  coal  per  day  at  $2  per  ton,  this 
would  cause  a  yearly  loss  of  about  $1,970.  It  is  essential  therefore 


34 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


to  save  the  3  per  cent  of  heat,  even  though  it  becomes  necessary 
to  use  another  pump,  but  this  is  objectionable,  as  it  makes  another 
machine  to  care  for,  watch  and  regulate. 

A  simple  solution  of  this  question  is  to  attach  the  pistons  of 
the  low  pressure  heater  supply  pump  to  the  plungers  of  the  feed 
pump,  in  such  a  way  that  they  can  readily  be  detached.  The  advan- 
tage of  this  arrangement  is  that  better  economy  is  secured,  there  is 
one  less  steam  end  to  look  after  and  there  is  no  liability  of  shortage 
nor  waste  of  heater  water.  The  amount  of  water  delivered  to  the 
heater  will  be  the  same  as  that  taken  from  it.  Therefore  it  is 
decided  to  use  a  double  water  end  feed  pump  arranged  so  that  the 
heater  supply  pump  can  be  quickly  disconnected  in  case  of  acci- 
dent, and  during  a  repair  water  would  be  taken  from  the  house 
service  line  by  means  of  the  fire  pump. 


FIG.  13.   System;  Feed  Water  Meter,  Simple  Plan. 

Next  comes  the  water  meter.  This  should  be  so  arranged  with 
respect  to  the  piping  that  the  total  water  fed  to  any  or  all  of  the 
boilers  can  be  measured,  whether  fed  through  the  economizers  or 
with  the  economizers  cut  out.  The  meter  should  also  be  arranged 
with  a  by-pass  so  that  it  can  ordinarily  be  out  of  service.  Fig.  13 
shows  one  system  of  feed  water  pipes  with  meter,  the  hydraulic  tube 
cleaner  line  being  also,  in  this  case,  an  auxiliary  feed  main.  This 
system  is  especially  suited  to  plans  that  have  one  economizer  to 
serve  one  side  of  the  plant.  It  will  be  noted  that  the  feed  water 
can  be  run  through  the  economizers  and  any  one  or  more  of  the 
boilers  fed  through  the  meter,  the  boilers  not  on  the  meter  being 
fed  through  the  regular  feed  main.  The  only  condition  that  could 
be  improved  is  in  the  case  of  feeding  with  the  economizer  cut 
out.  It  will  be  noted  that  when  metering  cold  feed  water,  even  if 
only  for  one  boiler,  all  the  other  boilers  would  have  to  take  cold 


PIPING   SYSTEMS. 


35 


feed  water  also.  The  system  shown  in  Fig.  13  requires  no  extra 
piping  for  the  meter  other  than  the  meter  connections  themselves. 
When  cleaning  the  boiler  tubes  the  meter  is  shut  off  as  well  as  all 
feeds  to  the  boilers,  and  the  regular  feed  main  is  used  for  boiler 


01 


FIG.  14.   System,  Feed  Water  Meter,  more  Flexible  Plan. 

feeding.  The  test  usually  made  with  economizers  is  to  meter  the 
water  for  all  boilers,  first  with  the  economizers  on  and  before 
cleaning  them,  second  with  the  economizers  off  and  third  with  the 
economizers  on  after  cleaning  them.  This  test  is  to  determine  how 


FIG.  15.    System,  Fig.  14,  with  Meter  out  of  Service. 

much  can  be  saved  by  reason  of  cleaning  them,  or,  in  other  words, 
to  determine  how  often  it  pays  to  clean  economizers,  how  well  to 
clean  them,  etc. 

Another  arrangement  in  piping  can  be  made,  as  shown  in  Fig. 
14,  which  will  provide  for  all  conditions  and  which  will  permit 
metering  cold  water  fed  to  one  boiler  and  feeding  through  the 
economizers  for  all  the  other  boilers.  Fig.  15  shows  the  regular 
method  of  operation  with  the  meter  out  of  service  and  the  hose 
main  ready  for  use.  The  feed  system  in  this  illustration  is  shown 
in  full  lines,  and  the  cleaner  system  is  dotted. 

Fig.  1 6  shows  the  meter  in  use  with  all  boilers  using  hot  water. 
By  opening  valve  a  and  closing  b,  cold  water  would  be  fed 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


through  the  meter  to  the  boiler.  The  dotted  lines  indicate  the 
portion  of  the  system  out  of  service,  though  this  portion  may  be 
under  pressure.  The  arrangement  shown  in  Fig.  16  would  permit 
the  water  meter  to  be  placed  on  the  floor  next  to  the  pumps, 
the  lines  cy  d  and  e  being  the  risers  from  the  latter.  After 


FIG.  16.   System,  Fig.  14,  with  Meter  in  Service. 

the  system  is  determined,  the  pipe  details  can  be  considerably 
simplified  by  changing  the  relative  location  of  lines,  etc.,  and  at 
the  same  time  maintain  the  same  system.  For  example,  Fig.  17 
shows  a  rearrangement  which  permits  the  meter  and  pump  connec- 
tions to  be  made  compact  and 
accessible  from  the  floor.  It  may 
be  found  that  the  pumps  cannot  both 
be  of  the  same  pattern  as  shown. 
The  distance  /  may  require  the 
pumps  to  be  right  and  left  handed 
with  their  steam  cylinders  together, 
in  order  to  leave  room  for  the  re- 
quired connections.  The  pumps 
must  not  determine  the  piping,  but 
the  piping  should  determine  the 


FIG.  17.   System;  Developing 
Detail  for  Fig.  14. 


minor  details,  such  as  those  just  mentioned. 

The  early  diagrams  made  for  a  station  should  be  considered  as 
studies  and  after  the  pipe  work  has  been  detailed  in  accordance  with 
these  diagrams  the  best  plan  would  then  be  to  change  the  direc- 
tion of  the  lines  on  the  final  diagram  so  that  they  will  correspond 
closely  with  the  lines  as  they  are  to  be  built.  This  will  enable 
the  men  in  the  station  to  read  the  diagram  much  more  readily  and 
with  less  liability  of  making  an  error  in  the  operation  of  the  valves. 
The  valves  should  be  shown  in  approximately  their  correct  location. 
For  instance,  when  Fig.  17  has  been  laid  out  in  detail  these  data 


PIPING   SYSTEMS. 


37 


should  be  used  for  correcting  the  diagram  as  illustrated  in  Fig.  14 
and  the  final  result  be  shown  as  in  Fig.  18.  At  first  glance  the 
system  shown  in  Fig.  18  appears  to  be  a  different  one  than  that 
shown  in  Fig.  14,  but  in  reality  it  is  exactly  the  same.  The  object 
in  correcting  the  final  diagram  is  to  avoid  this  deceptive  appearance. 
Fig.  12  shows  the  general  arrangement  which  will  be  used  in 
designing  the  problem  plant.  There  are  four  groups  of  econo- 
mizers shown  which  will  ordinarily  be  fed  from  one  pump.  If  the 
boiler  plant  were  divided  into  halves  and  each  half  provided  with 


FIG.  18.    System;  Rearrangement  of  Fig.  14  to  suit  Detail. 

its  own  economizers,  then  the  pumps  could  be  placed  at  the 
dividing  line  between  the  two  halves,  and  with  possibly  a  few 
modifications  in  regard  to  the  valves  Fig.  14  could  be  used.  After 
adding  the  connection  lines  between  the  two  halves  the  arrange- 
ment would  be  as  shown  by  Fig.  18. 

Having  decided  upon  the  general  arrangement  of  the  economizers 
and  boilers,  the  piping  should  now  be  laid  out  in  a  detailed  system. 
This  system  should  be  made  as  reliable  and  as  flexible  as  that 
shown  in  Fig.  14  and  by  tracing  out  Fig.  19  it  will  be  seen  that 
the  following  conditions  are  readily  secured: 

1.  Regular  operation  of  No.  i  pump  on  fire  line  and  house 
service;  No.  2  pump  on  auxiliary  main  for  tube  cleaning;  No.  3 
pump  on  feed  mains. 

2.  The  meter  can  be  used  with  either  pump  No.  2  or  No.  3  or 
with  both;  the  discharge  from  the  meter  can  be  fed  to  the  feed  main, 
auxiliary  main  or  to  both  at  the  same  time;  the  meter  can  deliver 
through  one  or  more  economizers  with  either  heater  water  or  cold 
water;  it  can  also  feed  direct  to  the  boilers  by  passing  one  or  more 
economizers. 

3.  Any  one  pump  may  be  shut  down  without  interfering  with 
regular  operation;  any  two  pumps  may  be  shut  down  ancl  still  main- 


38  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

tain  pressure  on  the  feed  main  and  the  house  service,  using  cold 
water  or  water  from  the  hot  well  in  the  economizers. 

4.  When  an  economizer  is  shut  off  the  boilers  which  regularly 
feed  through  it  can  get  feed  water  from  the  economizer  in  the  next 
battery  of  boilers. 

5.  The  entire  feed  main  may  be  shut  off  and  water  then  be  fed 
through  the  auxiliary  main  or  vice  versa. 

6.  The  auxiliary  main  may  feed  through  the  economizer  or 
directly  to  the  boilers. 

7.  During  the  winter,  warm  water  may  be  kept  on  the  fire  and 
house  service  system  by  using  the  hot  well  as  a  supply. 

This  system  necessitates  the  metering  of  the  water  used  in  two  of 
the  boilers  in  each  battery.  The  advantages  which  might  be  gained 
by  separately  metering  the  water  for  each  boiler  would  not  justify 
the  addition  of  the  piping  connections  necessary  to  accomplish  this 
detail.  If  it  is  found  necessary  to  make  a  separate  test  on  one  boiler 
this  can  be  done  when  the  other  boiler  is  shut  down,  or  if  it  is  neces- 
sary to  test  two  boilers  which  discharge  into  the  same  economizer, 
the  meter  reading  when  divided  by  two  would  hold,  because  the 
boiler  which  burned  the  greater  amount  of  coal  would  be  heating  the 
feed  water  for  the  other  boiler. 

The  chief  requirements  for  a  boiler  feed  system  are  well  cared 
for  in  Fig.  19.  They  are  as  follows: 

1.  Any  part  of  the  feed  system  may  be  shut  off  without  reduc- 
ing the  capacity  more  than  one-fourth,  for  four  units. 

2.  The  hot- well  water  may  be  fed  to  the  economizers  when  the 
heater  is  off. 

3.  The  boilers  with  economizers  off  may  take  their  feed  from 
any  other  economizers  which  are  in  operation. 

4.  An  abundance  of  feed  reserve  is  provided  for. 

There  are  various  other  systems  of  metering  which  might  be 
employed  such  as  a  separate  meter  for  each  boiler,  or  as  shown  in 
Fig.  19  a  separate  meter  with  a  by-pass  might  be  used  for  each 
economizer  if  placed  at  the  points  in  the  feed  system  marked  a. 
By  using  four  smaller  meters  they  could  be  operated  at  nearer  their 
normal  capacity  than  could  one  of  sufficient  size  to  care  for  the 
entire  plant,  thus  the  readings  would  be  more  accurate,  but  simpler 
and  more  accessible  details  can  be  obtained  by  using  one  large 
meter  at  the  pumps.  This  will  also  allow  the  meter  to  be  read 
from  the  pump  room  floor.  The  relative  performance  of  the  boiler 


PIPING   SYSTEMS. 


39 


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STEAM  POWER  PLANT  PIPING  SYSTEMS. 


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PIPING   SYSTEMS. 


units  can  be  determined  more  accurately  by  using  the  same  meter 
for  measuring  all  the  water.  Any  difference  in  the  performance 
which  might  be  shown  on  two  individual  boiler  meters  might  be 
due  to  one  or  both  of  the  meters  being  inaccurate.  With  but  one 
meter  the  degree  of  inaccuracy  will  show  the  same  for  all  boilers. 

City  water  connections  which  are  taken  from  a  meter  in  the  city 
water  works  line  should  have  a  line  carried  to  the  house  service 
main  and  a  branch  to  the  heater  so  that  when  it  is  necessary  to 
clean  out  or  shut  off  the  intake  there  will  be  another  source  of 
water  supply  for  boiler  feeding.  All  these  conditions  must  be  pro- 
vided for  because  no  one  can  foresee  the  many  difficulties  which 
may  come  up  and  it  is  safe  to  assume  that  every  line  and  connec- 
tion will  necessitate  shutting  down  sometime  without  giving  more 
than  a  moment's  warning. 

But  a  portion  of  the  fire  main  in  the  station  is  shown  in  Fig.  19. 
Ordinarily  a  safe  fire  and  house  service  can  be  laid  out  on  the  loop 
system  as  shown  in  Fig.  20.  Valves  should  be  arranged  so  that  any 
portion  of  the  loop  can  be  shut  off  and  still  have  a  partial  fire  protec- 
tion. The  very  important  connections,  such  as  the  water  to  the 
heater,  should  have  a  valve  on  either  side  of  them  as  shown  in  Fig.  2 1 
and  a  valve  between  the  two  separate  sources  of  supply;  then  any  sec- 
tion of  the  line  may  be  shut  off  and  water  still  delivered  to  the  heater. 

The  branches  to  the  roof,  city  line,  low  pressure  service,  other 
buildings  and  lawn  sprinklers  should  all  be  provided  for.     As  the 
points  to  be  brought  out  in  considering 
these  are  more  in  the  nature  of  details 
than  of  general  system,  they  will  be  con- 
sidered later.      Ordinarily  the  hydrants 
should  be  kept  away  from  the  outside 
walls  a  distance  not  less  than  the  height 
of  the  wall.  The  fire  mains  and  branches 
must  be  laid  below  frost  line,  the  depth 
of  which  can  be  obtained  from  a  neigh- 
boring  city   water  works.      Standpipes 
which  run  to  the  roof  and  any  hose  lines 
inside  of  the  buildings  should  have  an 
indicator  post  outside,  so  that  in  event  of    FIG.  21.  System;  Fire  Main 
piping  becoming  broken  or  bursting  from  supplying  F 
exposure  to  frost  the  water  can  be  shut  off  and  the  pressure  on  the 
fire  piping  maintained.     All  house  service  valves  when  connected 


cicb 


42  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

to  the  fire  mains  should  be  readily  accessible  so  that  in  case  of  fire 
they  may  be  closed  quickly.  Any  lawn  sprinklers  fed  from  the 
fire  lines  should  be  fully  able  to  stand  the  fire  pressure  and  should 
be  frost  proof. 

Before  making  a  final  decision  on  the  design  of  the  building  or 
piping  it  would  be  well  to  take  up  all  the  details  of  fire  protection 
with  the  board  of  underwriters  because  some  details  which  an  engi- 
neer would  consider  to  be  of  minor  importance  must  be  used  in  order 
that  the  underwriters'  rules  and  regulations  be  obeyed.  To  secure 
the  lowest  insurance  rates  it  will  be  necessary  to  install  such  details 


FIG.  22.   Sample  System;  Condenser  circulating  Water. 

as  they  require,  and  even  though  they  admit  that  some  of  their 
demands  are  at  times  unreasonable  they  are  without  authority  to 
modify  them. 

The  subject  of  artesian  wells  is  not  always  a  necessary  part  of 
power  station  work,  but  in  the  case  of  many  factory  plants  they 
cannot  very  readily  be  avoided  and  will  be  explained  later  by  means 
of  diagrams. 

Let  it  be  assumed  that  the  plant  in  question  is  located  alongside 
of  a  stream  of  water  suitable  for  boiler  feeding.  The  intakes,  dis- 
charges and  connections  to  circulating  pumps  and  condensers  of 
such  a  plant  are  shown  in  Fig.  22.  As  in  other  lines,  the  chief 
requirement  in  this  system  is  that  it  be  possible  to  shut  off  any  part 
of  the  system  and  yet  allow  three-fourths  of  the  plant  to  be  operated 


PIPING   SYSTEMS.  43 

The  waterway  A  is  always  an  intake,  the  waterway  C  is  always  a 
discharge,  the  waterway  B  may  be  either.  Any  one  of  these  three 
waterways  may  be  shut  off  at  any  time.  Either  of  the  lines  from 
the  intake  or  hot  well  to  the  pumps  may  be  shut  down  and  operation 
continued  with  the  other.  Any  portion  of  the  discharge  main  from 
the  circulating  pumps  may  be  shut  down  and  the  operation  of  one 
condenser  still  permitted.  Any  one  of  the  three  circulating  pumps 
can  supply  water  to  either  of  the  condensers.  All  lines  are  so  con- 
nected that  repairs  can  be  easily  made. 

At  first  thought  it  would  possibly  seem  that  too  many  valves  are 
used  to  make  this  system  reliable.  On  noting  the  suction  and  dis- 
charge of  the  circulating  pumps  it  will  be  seen  that  there  are  seven 
valves  on  the  suction  side  and  seven  on  the  discharge.  By  disre- 
garding the  making  of  pipe  work  at  all  times  accessible  a  shut-off 
valve  would  still  be  required  for  each  machine,  each  condenser  and 
each  source  of  supply  such  as  intakes  B  and  C,  and  if  the  factor  of 
readily  made  repairs  to  the  lines  is  also  disregarded  it  will  be  found 
that  out  of  a  total  of  18  valves  but  4  can  be  saved;  thus  it  is  seen 
that  with  an  increase  of  about  5  per  cent  in  the  cost  of  pipe  work 
the  line  may  be  made  entirely  accessible.  The  piping  cost  is 
ordinarily  about  5  to  7  per  cent  of  the  total  station  cost  for  such  a 
plant  as  is  being  outlined,  so  the  difference  in  the  cost  of  a  station 
having  an  inaccessible  system  and  one  having  a  readily  accessible 
system  would  be  about  one-fourth  of  one  per  cent  of  the  total  station 
cost  or  about  25  cents  per  kilowatt  increased  cost  for  valves,  and  if 
10  cents  be  allowed  for  extra  labor,  fitting,  etc.,  the  total  added 
cost  would  be  but  35  cents  per  kilowatt  or  one-third  of  one  per  cent 
of  the  total  cost  of  the  station.  The  cost  should  not  be  considered. 
The  only  factor  should  be  the  time  and  study  necessary  to  perfect 
the  layout  and  provide  the  station  with  a  flexible  and  reliable 
system. 

In  case  three  waterways  are  used  instead  of  two,  there  would  be 
a  slight  additional  expense  in  the  first  cost,  but  the  expense  of  opera- 
tion would  be  lessened  because  one  screen  house  could  be  shut 
down  and  cleaned  of  any  sediment  or  obstruction  while  the  other 
two  fed  the  plant,  and  during  the  winter  months  the  waterways  B 
and  C-  may  be  used  and  the  liability  for  interference  from  ice  be 
lessened  by  the  warm  water  discharging  close  to  the  intake.  During 
the  warmer  months  of  the  year  waterways  A  and  C  could  be  used 
since  they  are  placed  at  a  considerable  distance  from  each  other. 


CHAPTER  IV. 
CONDENSERS  AND  HEATERS. 

BEFORE  taking  up  any  of  the  other  systems  for  the  station  in 
question  there  will  be  considered  the  requirements  for  a  condensing 
plant  having  an  artesian  well  and  using  cooling  towers  and  a  surface 
condenser.  The  most  difficult  feature  to  contend  with  in  connec- 
tion with  using  cooled  water  is  that  arising  from  the  use  of  oil  in 
engine  cylinders.  This  type  of  condensing  plant  retains  all  the 


FIG.  23.   Complex  System;  Artesian  Water,  Chemical  Treatment,  Cooling  Tower, 

and  Condensers. 

solids  and  the  objectional  matter  contained  in  the  water  because 
the  vaporization  due  to  cooling  the  water  carries  away  only  the  pure 
v/ater  vapor.  There  is  an  opportunity  for  much  study  in  regard 
to  a  system  and  apparatus  to  be  used  in  such  a  condensing  plant. 
The  elevated  jet  type  of  condenser  in  which  the  circulating  water 
is  not  used  for  boiler  feeding  is  shown  in  Fig.  23.  Artesian  well 
water  ordinarily  contains  large  quantities  of  lime  and  magnesia, 

44 


CONDENSERS  AND  HEATERS.  45 

making  it  necessary  to  remove  these  before  feeding  this  water  to  the 
boilers.  The  amount  of  water  in  the  form  of  vapor  which  would 
be  lost  while  being  cooled  would  be  replaced  chiefly  by  condensa- 
tion added  in  the  condenser  and  still  more  water  would  be  added 
through  a  line  from  the  deep  well  basin  to  the  circulating  pump. 
The  loss  in  circulating  water  is  greater  than  that  required  for  the 
boilers,  so  the  feed  which  requires  the  least  addition  will  be  treated. 
By  treating  the  boiler  feed  direct  from  the  well  all  difficulties  from 
cylinder  oil,  etc.,  are  avoided. 

To  retain  the  heat  which  would  ordinarily  be  saved  by  using  hot- 
well  water  a  vacuum  exhaust  heater  A  and  an  open  atmospheric  ex- 
haust heater  B  for  additional  heating  would  be  used.  Since  the  feed 
water  temperature  would  be  as  low  with  this  system  as  with  any 
other  condensing  arrangement  the  using  of  economizers,  though  not 
shown  in  Fig.  23,  should  be  considered.  The  system  here  shown  is 
practical  but  very  expensive  both  to  install  and  operate.  The  addi- 
tional expense  of  installation  of  the  system  shown  in  Fig.  23  would 
be: 

1.  Cost  of  sinking  well,  deep  well  machinery,  building,  etc. 

2.  Cost  of  chemical  treating  plant,  building,  pump,  etc. 

3.  Cost  of  cooling  tower,  fans  and  motors,  pump  and  motor  and 
building  for  the  tower  installation. 

4.  Cost  of  vacuum  exhaust  heater,  by-passes,  etc. 
The  additional  operating  expenses  would  be: 

1.  Raising  deep  well  water  to  its  basin. 

2.  Raising  water  to  chemical  tanks. 

3.  Raising  water  to  top  of  cooling  tower. 

4.  Power  to  operate  cooling  fans. 

5.  Cost  of  chemicals  for  treating. 

6.  Increased  labor  to  operate  and  maintain  additional  apparatus. 
The  arrangement  shown  in  Fig.  23  may  be  simplified  by  using  a 

surface  instead  of  a  jet  condenser  and  omitting  the  use  of  the  chem- 
ical treating  plant.  This  will  necessitate  the  installation  of  an  extra 
large  grease  extractor  in  the  exhaust  main  and  a  large  filter  bed  in 
the  heater.  Fig.  24  shows  such  a  system  laid  out  so  that  repairs 
may  be  easily  made.  It  will  be  noticed  that  the  large  water  basin 
may  be  completely  shut  off  by  closing  valves  A,  B  and  C,  thus  allow- 
ing water  to  raise  in  the  cooling  tower  basin  and  flow  back  into  the 
cold  water  basin.  During  the  time  when  the  cold  water  basin  is 
used  as  a  supply  for  the  condensers,  the  house  service  including  the 


46 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


FIG.  24.   System;  Artesian  Water,  Surface  Condensers,  and  Cooling  Tower. 


CONDENSERS  AND   HEATERS.  47 

drinking  and  journal  cooling  water  would  be  taken  from  the  city 
water  connection.  During  regular  service  the  deep  well  pump 
would  discharge  into  the  cold  water  basin  and  the  overflow  would 
run  into  the  cooling  tower  basin.  The  air  traps  at  the  water  dis- 
charges of  the  cooling  towers  are  not  shown  with  the  diagrams 
because  no  attempt  is  being  made  to  show  detail  in  connections. 
Note  will  also  be  taken  that  the  heater  and  heater  suction  may  be 
shut  off  and  the  wet  vacuum  pumps  have  another  connection 
through  which  to  discharge  condensation  to  the  pump  suction 
other  than  by  way  of  the  heater.  Any  portion  of  the  piping  shown 
or  any  device  may  be  shut  off  from  service  and  one  condenser  still 
be  run. 

Particular  note  will  also  be  taken  in  regard  to  cross  connections 
from  one  machine  to  another,  for  instance  if  No.  i  condenser,  cir- 
culating pump  and  wet  vacuum  pump  be  running  and  either  of  the 
pumps  necessitates  shutting  down,  it  is  then  possible  to  put  No.  2 
machine  into  operation  serving  No.  i  condenser,  and  not  shut  down 
the  No.  i  machine  until  No.  2  is  in  operation  and  supplying  No.  i 
condenser.  When  one  condenser  is  out  of  service  the  other  can  be 
readily  run  and  two  circulating  pumps  used  on  it.  This  system 
enables  perfect  operation  even  though  there  be  a  circulating  pump 
of  one  unit,  and  a  condenser  of  the  other  unit  out  of  service. 

In  a  piping  system  there  should  be  no  machine  piped  direct  to 
another  without  cross  connections,  so  that  the  shutting  down  of  one 
would  require  the  shutting  down  of  the  other.  There  should  be 
two  separate  sources  of  supply  and  two  ways  of  discharge,  with  one 
machine  on  either  end  and  the  cross  connections  so  arranged  that 
either  or  both  machines  could  use  either  supply  or  discharge.  This 
is  absolutely  essential  because  it  allows  for  repairing  the  pipe  line 
or  machines.  The  system  shown  in  Fig.  24  is  about  the  most  satis- 
factory arrangement  which  can  be  laid  out  for  an  artesian  well,  cool- 
ing tower  and  condensing  apparatus.  The  boilers  would  be  fed 
with  condensed  steam  and  only  that  water  lost  by  leakage  at  the 
joints,  exhaust  drips,  etc.,  would  need  to  be  replaced.  In  a  surface 
condensing  plant  the  steam  for  the  feed  pumps  would  be  somewhat 
differently  arranged  than  in  a  jet  condensing  plant.  The  method 
of  supplying  water  to  the  heater  and  steam  pumps  would  be  the 
same  for  a  jet  condenser  plant  as  for  a  non-condensing  station. 
This  detail  will  be  taken  up  later.  , 

In  the  heater  and  pump  arrangement  for  a  surface  condensing 


48  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

plant  as  in  Fig.  25,  the  condensed  steam  from  the  condenser  is  free 
to  be  discharged  into  the  heater  and  the  speed  of  the  pump  is 
governed  by  the  water  level  in  the  heater.  The  only  hand  control 
is  a  valve  in  the  make-up  water  line.  This  line  replaces  the  water 
which  has  been  lost  by  leakage,  drips,  etc.;  the  loss  is  a  steady, 
invariable  quantity,  therefore  the  valve  requires  but  little  attention 
when  slight  variations  in  the  relative  water  level  of  two  boilers  may 
be  controlled  by  the  boiler  feed  valves.  If  during  the  day  the  fire- 


FlG.  25.   System;   Controlling  Feed  Pump,  Open  Heater,  and  Surface  Condenser. 

man  observes  that  the  total  water  in  all  boilers  is  becoming  low  or 
high  he  slightly  adjusts  the  make-up  water  valve.  The  advantage 
of  this  style  of  governing  is  that  regulation  is  required  for  an  almost 
constant  demand  caused  by  leakage,  drips,  etc.  It  is  not  practical 
with  this  style  of  condenser  to  leave  the  pump  control  to  a  fireman 
when  he  has  no  control  of  the  incoming  condensation.  If  so, 
it  is  fair  to  presume  that  fully  one- third  of  the  return  condensation 
would  go  to  the  sewer.  The  object  in  using  a  surface  condenser 
is  to  be  able  to  save  all  the  condensation  for  the  boilers,  thus  using 
very  little  new  water.  This  can  be  accomplished  only  by  connecting 
the  float  valve  to  the  pump  steam  connection,  and  if  it  is  desired 
at  any  time  to  skim  off  the  top  of  the  heater  water  this  can  readily 
be  done  by  shutting  steam  off  the  pump  for  a  minute  or  so. 

The   heater   manufacturer  will   possibly   oppose   this   style   of 
governing,  claiming  that  it  is  not  the  regular  method.     For  all 


CONDENSERS  AND   HEATERS. 


49 


other  applications  their  method  as  shown  by  Fig.  26  is  correct  but 
for  surface  condenser  it  is  radically  wrong.  The  absurd  claim  is 
sometimes  made  that  when  a  heavy  load  comes  on,  the  boilers 
would  evaporate  water  to  a  low  water  level  and  it  should  be  possible 
for  the  fireman  to  speed  up  the  pump  in  order  to  increase  the  water 
in  the  boilers.  The  velocity  of  steam  in  pipe  lines  should  not  be 
taken  at  less  than  1,000  ft.  per  minute  and  with  this  speed  it  would 
take  about  five  seconds  for  steam  to  leave  the  boiler,  reach  the  con- 


FIG.  26.   System;  Controlling  Feed  Pump,  Open  Heater,  and  Jet  Condenser. 

denser,  and  be  condensed  ready  to  deliver  back  to  the  heater.  The 
fireman  would  not  have  time  to  even  see  the  change  in  the  boiler 
water  level  by  the  time  the  feed  pumps  were  under  control  of  the 
changed  condition. 

The  system  shown  in  Fig.  25  is  not  suitable  for  a  non-condensing 
or  for  a  jet  condenser  plant,  but  it  is  desirable  for  the  returns  of  a 
heating  system  which  is  also  a  surface  condenser.  In  Fig.  26  is 
shown  the  regular  method  of  heater  connections  using  a  float 
control  valve  in  the  water  supply  line.  Line  A  is  the  discharge  from 
the  steam  traps,  etc.,  which  must  be  left  open  at  all  times.  This 
would  also  be  the  discharge  from  the  wet  vacuum  pump  in  case 
Fig.  26  were  used  for  a  surface  condenser  system.  The  line  A 
should  deliver  to  the  heater  a  lesser  amount  than  that  required  for 
the  feed  water  because  the  boilers  and  the  pump  should  never  be 


STEAM   POWER  PLANT  PIPING  SYSTEMS. 


run  slower  than  is  necessary  to  remove  the  incoming  water  from 
the  heater.  For  the  station  in  question  since  we  are  using  jet 
condensers,  we  will  use  the  system  shown  in  Fig.  26,  that  is,  the 
line  A  will  be  the  discharge  from  the  heater  pumps  and  the  float 
operated  valve  will  be  on  a  branch  from  the  house  service  line. 
The  float  operated  valve  will  be  out  of  sen-ice  for  the  greater 
part  of  the  time  during  regular  operation  of  the  heater  pumps,  be- 
cause these  pumps  will  deliver  to  the  heater  the  same  amount  of  water 
as  the  feed  pumps  would  take  away.  In  case  the  hdater  pumps 
are  not  being  used,  the  heater  supply  is  to  be  controlled  wholly 
by  the  float  operated  valve. 

Referring  to  Figs.  22,  23,  and  24  it  will  be  noted  that  the  dry 
vacuum  pumps  are  not  shown.  The  dry  vacuum  system  wrould  be 
the  same  for  either  style  of  condenser  but  if  a  surface  condenser 
were  used  there  should  be  two  of  these  pumps  to  insure  continuous 

operation.  A  surface  con- 
denser accumulates  air  un- 
til the  vacuum  is  lost  but  an 
elevated  jet  condenser  will 
discharge  a  large  portion 
of  the  air  due  to  the  great 
quantity  of  downward  flow- 
ing cooling  water  being 
mingled  with  the  air.  An 
elevated  jet  condenser  will 
ordinarily  drop  its  vacuum 
about  4  in.  when  running 
without  the  dry  vacuum 
pump,  in  fact  the  syphon 
type  elevated  jet  condenser 
is  installed  without  an  air 
pump  operating  at  a  slightly 
lower  vacuum.  Fig.  27 
shows  the  two  condensers  piped  to  an  air  pump  and  having  the 
valves  placed  as  closely  as  possible  to  the  pump  in  order  that  the 
number  of  joints  and  fittings  between  the  shut-off  valves  and 
the  pump  may  be  reduced.  To  make  repairs  between  the  valves 
and  pump  necessitates  shutting  down  the  pump  but  any  other 
repairs  can  be  made  and  one  condenser  still  be  in  operation. 
The  air  cooler  drains  back  into  the  tail-pipe  or  hot  well,  the  in- 


FIG.  27.   System;   Air  from  Elevated  Jet 
Condenser  to  Dry  Vacuum  Pumps. 


CONDENSERS   AND   HEATERS.  51 

jection  water  passing  through  the  cooler  on  its  way  to  the  condenser. 
The  air  pump  is  shown  discharging  over  the  hot  well  but  may  dis- 
charge over  a  sewer  catch  basin  as  there  is  no  appreciable  vapor. 
Another  method  is  to  discharge  the  air  into  the  tail-pipe  shown  by 
the  dotted  lines.  The  advantage  of  this  arrangement  is  that  air 
showing,  say  26  in.  vacuum,  is  taken  from  the  condenser  bowl  and 
discharged  into  the  tail-pipe  where  it  would  show  but  20  in.  of 
vacuum;  thus  instead  of  compressing  7  cu.  ft.  to  i  cu.  ft.  as  would 
be  the  case  if  exhausting  to  atmospheric  pressure,  it  is  necessary  to 
compress  but  2^  cu.  ft.  to  i  cu.  ft.  This  arrangement  would  not 
permit  raising  the  vacuum  on  the  condenser  when  starting  and  the 
atmospheric  vent  would  have  to  be  used  until  the  vacuum  was  on 
the  condenser  and  the  water  flowing  through  the  injector  shaped 
air  discharge  in  the  tail-pipe.  The  air  cooler  shown  is  used  on  jet 


FIG.  28.    System;  Removing  Air  from  Counter  Current  Surface  Condensers. 

condensers  only,  the  surface  condensers  admit  the  cooling  water 
to  the  condensing  tubes  in  contact  with  the  outgoing  air.  In  addi- 
tion to  cooling  the  air  it  is  also  necessary  to  cool  the  air  cylinders 
of  the  dry  vacuum  pump,  otherwise  the  high  temperature  due  to 
compression  will  prevent  proper  lubrication. 

Different  methods  are  used  for  removing  the  air  from  surface 
condensers.  Fig.  28  shows  the  counter  current  system.  The 
exhaust  steam  enters  beneath  the  cooling  tubes  and  the  air  is  with- 
drawn from  the  top  of  the  condenser.  The  condensation  makes 
its  last  pass  over  the  hottest  tubes  and  therefore  through  highest 
temperature  in  the  condenser.  The  air  which  is  removed  from  the 
upper  portion  of  the  condenser  by  the  action  of  an  air  pump  is  in 
contact  with  the  tubes  which  contain  the  cold  incoming  circulating 


52  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

water.  Evidently  the  air  must  be  in  a  continual  state  of  unrest  due 
to  the  counter  current  action.  The  weight  of  saturated  air  at  the 
temperature  in  a  condenser  is  about  0.06  Ib.  and  steam  about 
0.03  Ib.,  per  cu.  ft.  If  it  were  not  for  the  exhaust  steam  entering  the 
lower  part  of  the  condenser  and  being  deflected  over  the  entire  base 
it  would  be  possible  for  air  to  settle  to  the  base  of  the  condenser, 
but  instead  it  can  drop  only  into  the  current  of  incoming  steam  and 
therefore  be  constantly  carried  upward.  Air  cannot  remain  in 
pockets  at  the  upper  portion  of  the  shell  because  it  is  heavier  than1 
steam  and  will  therefore  drop  and  be  caught  in  the  steam  current. 


FIG.  29.   System;  Removing  Air  from  Direct  Current  Surface  Condensers. 

The  fact  that  this  type  of  condenser  has  shown  itself  to  be  very 
effective  is  sufficient  proof  of  the  merits  of  this  most  unusual  method 
for  removing  air  from  a  condensing  chamber. 

A  more  usual  type  of  condenser  is  shown  in  Fig.  29;  the  exhaust 
enters  the  top  and  together  with  air  passes  towards  the  bottom  of 
the  condenser,  the  air  dropping  to  the  base  of  the  condenser  and 
" flowing"  away  with  the  condensation.  It  is  not  the  intention  here 
to  give  the  "selling  points"  of  different  types  of  apparatus  but  these 
two  styles  of  condensers  differ  so  greatly  in  their  system  for  re- 
moving air  that  they  have  been  described.  In  fact,  the  elevated  jet 
type  of  condensers  is  also  made  in  these  two  styles.  In  the  counter 
current  type,  the  steam  enters  below  the  water  spray  and  flows 
upward  retarding  instead  of  accelerating  the  fall  of  the  injector 
water  after  leaving  the  spray  pan.  The  air  is  taken  from  the  upper 
portion  of  the  chamber  instead  of  the  lower  as  the  steam  entering 
the  lower  portion  prevents  the  air  from  precipitating.  This  method 
of  removing  air  must  be  more  effective  for  both  jet  and  surface 
type  condenser  judging  by  the  excellent  results  obtained  from  them. 


CONDENSERS    AND    HEATERS. 


53 


In  removing  air  from  either  an  open  or  closed  exhaust  heater 
having  an  insufficient  supply  of  steam,  the  air  should  be  led  off  at 
the  water  line  and  not  at  the  top  of  the  steam  chamber.  In  cases 
where  all  or  a  large  portion  of  the  steam  from  a  non-condensing 
plant  passes  through  the  heater,  air  will  be  removed  by  the  rapid 


FIG.  30.  System;  Improperly  Arranged 
for  Removing  Air  from  an  Induction 
Open  Heater  of  Insufficient  Steam 
Supply. 


FIG.  31.  System;  Properly 
Arranged  to  Remove  Air 
in  Open  Heater  of  Insuf- 
ficient Steam  Supply. 


flow  of  the  steam,  provided  the  openings  in  the  heater  are  properly 
arranged.  Fig.  30  shows  an  ordinary  heater  connection  which  is 
radically  wrong,  the  small  air  vent  A  being  wrongly  placed,  so  that 
the  flow  through  the  side  and  top  connection  is  very  slight;  in  fact, 
too  slight  to  carry  out  air  by  the  velocity  flow  through  the  heater. 
The  correct  method  is  shown  in  Fig.  31, 
which  may  appear  wrong  until  more 
fully  considered.  The  exhaust  enters 
the  top  and  causing  no  eddy  currents 
will  drop  to  the  water  line  and  if  the 
valve  B  is  open  will  pass  away  to  a 
point  of  lower  pressure. 

Heaters  can  also  be  styled  direct  and 
counter  current,  the  same  as  jet  or  sur- 
face condensers,  or  open  spray  or  closed 

tube  type   of  heater.      Figs.  32  and  33    FIG.  32.   System;  Passing  Entire 

show  the  counter  current  type,  the  air      H°Jautmre  Steam  throu8h  °Pen 
being  constantly  in  a  state  of  unrest 

and  due  to  the  large  volume  of  surplus  exhaust  passing  to  the 
atmosphere  the  air  will  drop  into  the  current  of  the  steam  and  be 


54 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


carried  out  of  the  heater.  This  type  of  connection  would  show 
better  efficiency  than  Fig.  35  because  as  in  counter  current  sur- 
face condensers  air  would  not  be  carried  to  a  point  where  it  would 
remain  stagnant  and  thus  insulate  any  heat  conducting  surface. 
The  heaters  shown  in  Figs.  31  and  34  are  specially  suited  for  use 


FIG.  33.  System;  Passing 
Entire  Volume  Steam 
through  Closed  Heater. 


FIG.  34.  System;  Passing 
Small  Volume  Steam 
into  Closed  Heater. 


FIG.  35.  System;  Passing 
Entire  Steam  improperly 
through  Closed  Heater. 


in  condensing  plants  where  the  amount  of  exhaust  steam  supplied 
the  heater  is  too  slight  to  cause  enough  upward  flow  to  carry  air 
with  it.  The  valve  B,  shown  in  Fig.  31  and  Fig.  34,  should  be  of 
a  globe  or  gate  type  and  not  a  back  pressure  valve  as  it  is  very 
necessary  to  prevent  a  vacuum  on  the  heater  unless  the  apparatus 
is  specially  arranged  to  stand  such  pressure.  The  heaters  shown 
in  Figs.  32  and  33  are  specially  suited  for  use  where  there  is 
sufficient  exhaust  to  maintain  pressure  in  heater  above  that  of  the 
atmosphere. 


CHAPTER    V. 
LIVE  STEAM  DRIPS. 

THE  system  for  supplying  live  steam  will  next  be  considered 
and  with  this  topic  live  steam  drips  will  be  described.  A  general 
arrangement  which  will  serve  these  purposes  is  illustrated  in 
a  preliminary  way  by  Fig.  10,  the  different  lines  being  subject 
to  revision  upon  more  careful  consideration.  The  general  detail 


FIG.  36.   System;  Gravity  Return  of  Steam  Drips. 

of  the  location  of  the  drips  will  now  be  considered,  even  before 
determining  the  main  steam  connections. 

In  Fig.  36  is  illustrated  a  gravity  drip  return  system.  The 
branches  of  the  piping  system  which  carry  live  steam  from  the 
boilers  drain  into  the  header  and  this  in  turn  drains  into  the 
separators  which  are  placed  in  the  engine  branches.  The  steam 
used  in  the  low  pressure  reheater  receiver  is  led  off  a  short  distance 

55 


56  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

above  the  bottom  of  the  separators  and,  as  shown  in  Fig.  36,  the 
separator  drips  are  run  to  an  accumulator,  each  pipe  having  a 
regulating  valve  in  it.  If  by  accident  the  drain  leading  off  from 
the  bottom  of  the  separator  be  closed  too  much  to  take  away  the 
drip,  then  a  passage  will  still  be  open  by  way  of  the  pipe  to  the 
reheater  receiver  and  thence  to  the  accumulator.  The  elevated 
drip  separator  is  placed  at  a  sufficient  height  to  insure  that  the 
drip  will  flow  into  the  boilers. 

For  part  or  all  of  the  auxiliaries  steam  is  taken  from  the  upper 
portion  of  the  receiver  and  the  small  amount  of  condensation  which 
may  be  in  the  auxiliary  main  is  led  to  the  heater  by  means  of  a 
bleeder  or  trap.' 

In  operating  this  system  where  there  are,  say,  10  connections  into 
the  accumulator,  two  for  each  of  the  four  generating  upits  and 
one  for  each  of  the  exciter  units,  it  is  necessary  that  each  drain 
be  sufficiently  open  to  permit  draining  the  line  to  which  it  is  at- 
tached, but  sufficiently  closed  to  offer  a  noticeable  resistance  to  the 
flow,  thus  allowing  the  auxiliaries  to  be  under  a  slightly  less  pres- 
sure than  the  main  steam  line.  The  discharge  from  the  drip  sepa- 
rator is  carried  to  a  drip  main  having  branches  to  each  of  the 
boilers  and  stop  and  check  valves  in  each  branch.  In  such  a 
system  the  difference  in  the  pressures  in  separator  and  steam 
header  is  greatest  just  before  a  "slug"  of  water  is  carried  up  the 
standpipe  into  the  drip  separator,  then  as  soon  as  the  water  is  out 
of  the  way  the  difference  in  the  two  pressures  is  only  that  due  to 
friction.  The  chief  advantage  of  such  a  system  is  that  neither 
floats  nor  automatic  devices  are  required  for  its  operation,  in  fact 
there  is  no  mechanism  employed.  To  start  the  system  the  bleeder 
to  the  heater  is  opened  in  order  to  clear  the  lines  to  the  point  of 
receiving  steam,  then  the  auxiliary  is  started  and  as  long  as  there 
are  auxiliaries  running  this  system  will  remain  open. 

Another  method  of  returning  drips  to  the  boilers,  illustrated  in 
Fig-  37,  is  by  using  a  drip  receiver  in  which  is  placed  a  float  so 
connected  that  it  regulates  the  speed  of  the  pump.  This  system 
has  the  advantage  that  it  is  easily  understood  and  therefore  will 
be  more  likely  to  be  operated  properly  than  the  system  shown  in 
Fig.  36,  which  requires  someone  to  instruct  the  attendants  what  to 
do  and  see  that  these  instructions  are  properly  obeyed.  Careful 
watch  must  be  kept  over  the  system  shown  in  Fig.  36  if  the  drip 
is  to  be  returned  to  the  boilers  and  not  be  wasted  into  the  sewer. 


LIVE   STEAM   DRIPS. 


57 


The  difference  in  the  costs  of  these  two  systems  is  not  sufficient  to 
be  considered.  The  initial  cost  of  the  system  shown  in  Fig.  37 
is  less  than  that  of  Fig.  36,  but  the  maintenance  for  Fig.  37  is 
greater.  The  maintenance  for  Fig.  36  is  very  slight. 

There  is  still  another  system  which  combines  as  low  first  cost, 
low  maintenance  cost,  simplicity  and  high  efficiency  as  can  be  ar- 
ranged for  a  condensing  plant  not  using  economizers.  This  system 
is  illustrated  in  Fig.  38  and  discharges  the  drip  into  an  open  heater 
when  so  arranged  that  exhaust  steam  and  drips  do  not  raise  the 
temperature  to  210  degrees,  thereby  allowing  a  waste  of  steam. 
Traps  are  not  very  desirable  pieces  of  station  apparatus,  but  by 
using  two  as  shown  and  the  by-passes,  a  very  reliable  system  is 
obtained. 

It  will  be  noticed  that  Figs.  36  and  37  show  steam  drips  dis- 
charging direct  to  the  boilers  and  not  by  way  of  the  feed  main. 
This  is  an  essential  feature  because  the  feed  main  pressure  may  be 


FIG.  37.   System;  Return  of  Steam 
Drips  by  Pump. 


FIG.  38.   System;  Discharge  of 
Steam  Drips  to  Heater  by  Trap. 


lowered  at  any  time  until  it  becomes  less  than  the  steam  pressure. 
Such  a  condition  may  be  caused  by  the  stopping  of  the  feed  pump, 
thus  allowing  the  water  pressure  to  escape  through  the  pump 
valves,  or  it  may  be  due  to  the  filling  of  an  empty  boiler,  or  the 
blowing  off  of  an  economizer.  In  any  case,  whenever  the  pressure 
in  the  feed  main  is  lower  than  the  steam  pressure,  the  steam  if  not 
checked  will  force  the  feed  water  back  and  cause  very  serious 
damage.  An  automatic  pump  between  the  steam  and  feed  lines 
is  no  barrier  whatever,  because  the  steam  at  boiler  pressure  will 
open  and  pass  through  the  pump  valves,  even  when  the  pump  is 
not  running.  For  the  same  reason  an  automatic  drip  pump  cannot 
be  used  to  discharge  into  an  open  heater  or  another  receptacle 
which  is  under  less  than  boiler  pressure.  The  discharge  pressure 


58  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

must  always  be  greater  than  the  suction,  even  though  it  be  caused 
by  only  a  short  column  of  water  additional.  The  discharge  line 
from  the  automatic  pump  should  have  a  relief  valve  placed 
between  the  pump  and  any  valve  that  may  be  placed  in  this  line, 
and  the  discharge  should  then  be  piped  to  a  catch  basin  where  the 
end  of  the  pipe  is  open  so  that  any  discharge  which  is  taking 
place  may  be  seen.  This  relief  valve  is  very  essential  in  order 
that  the  pump  and  pipe  line  may  be  protected  in  case  all  discharge 
valves  should  be  closed.  It  is  possible  for  the  automatic  pump, 
which  receives  its  suction  under  boiler  pressure,  to  more  than 
double  the  steam  pressure  on  a  discharge  ;  the  steam  end  of  the 
pump  ordinarily  has  twice  the  area  of  the  water  end  and  therefore 
when  the  steam  pressure  is  but  175  Ib.  per  sq.  in.  a  pressure  of 
from  350  to  400  Ib.  per  sq.  in.  can  easily  be  obtained  in  case  the 
discharge  pipe  is  closed.  Unless  the  lines  and  pumps  be  built  for 
such  pressures  breakdowns  must  occur,  because  when  shutting 
down  the  boiler  it  is  quite  a  simple  oversight  for  an  operator  to 
close  the  automatic  pump  discharge  and  not  notice  that  there  is  no 
other  way  of  discharge. 

Another  method  of  returning  drips  to  the  boilers  is  illustrated 
in  Fig.  39.  This  arrangement  can  be  used  only  in  connection  with 
single  acting  pumps  and  in  systems  where  there  is  but  one  pump 
on  the  line  and  the  header  is  not  less  than 
5  ft.  above  the  water  line  of  the  boilers.  The 
operation  of  this  system  is  made  possible  by 
the  pulsating  pressure  which  is  present  during 
the  operation  of  single  acting  pumps.  If  such 
PumPs  carried  a  uniform  pressure  this  system 
would  not  be  feasible.  A  single  acting  pump 
discharges  a  cylinder  full  of  water,  then  stops  at 

C    inertia  of   the 


sation  of  Feed  Pump.  water  is  only  overcome  by  meeting  the  boiler- 
water  which  has  a  higher  pressure;  while  the 
discharge  from  the  pump  is  being  brought  to  a  state  of  rest  and 
the  pressure  in  the  part  of  the  system  next  to  the  pump  is  lower 
than  the  boiler  pressure,  the  drip  line  which  is  at  boiler  pressure 
flows  into  this  part  of  the  system  and  before  the  returning  stroke 
of  the  pump,  the  pressure  in  the  discharge  is  again  returned  to 
boiler  pressure.  For  a  small  installation  this  method  of  drain- 
ing the  steam  main  would  appeal  to  an  engineer  on  account  of 


L1VR  STEAM  DRIPS.  $9 

its  extreme  simplicity,  but  for  a  large  plant  it  might  be  found 
difficult  to  maintain  the  entire  arrangement  as  shown.  This 
pounding  action  in  the  feed  mains  would  not  be  considered  very 
favorably  in  large  station  work,  and  without  the  pounding  this 
system  would  necessarily  be  inoperative.  This  system  also  has  a" 
bad  feature  because  it  discharges  into  the  feed  main  and  not  into 
the  boiler  direct. 

For  the  station  being  studied,  Fig.  36  may  be  used  as  the  drip 
system,  and  when  this  figure  is  arranged  in  a  flexible  form  it  appears 
as  shown  in  Fig.  40.  It  will  be  noted  that  any  or  all  of  the  auxil- 
iaries can  be  supplied  with  steam  through  this  drip  system. 
Ordinarily  steam  required  for  one  or  two  of  these  machines  should 
be  taken  from  the  drip  system,  to  avoid  reducing  the  pressure  in 
the  drip  separator  to  such  a  point  that  the  drips  will  not  flow  back 
to  the  boiler.  In  event  that  no  auxiliary  is  taking  steam  from  the 
circulation  pipe  A  it  would  be  necessary  to  blow  steam  into 
the  heater  or  to  the  atmosphere,  and  unless  this  operation  is  prop- 
erly carried  out  the  steam  thus  blown  through  the  system  would  be 
more  than  that  required  to  run  a  portion  of  the  auxiliaries.  In 
riser  B  pressure  is  required  to  elevate  the  drips,  as  is  a  pressure 
also  necessary  in  the  drip  separator  to  return  the  drips  to  the 
boiler.  The  pressure  in  the  separator,  however,  is»but  very  few 
pounds  less  than  boiler  pressure,  and  so  within  the  maximum  and 
minimum  limits  of  the  allowable  flow  of  line  B  the  return  of  drips 
is  possible. 

In  case  the  steam  for  one  fan  engine  is  found  sufficient  to  handle 
the  drips,  valve  C  may  be  closed;  in  case  the  fan  engine  requires 
more  steam  than  can  pass  through  lines  B  and  A ,  and  at  the  same 
time  maintain  sufficient  pressure  in  the  drip  separator  to  dis- 
charge water  to  the  boilers,  it  would  be  possible  to  make  C  a 
reducing  valve  allowing,  say,  3  Ib.  difference  on  the  two  sides  of  the 
valve,  thus  furnishing  a  portion  of  the  steam  for  the  fan  engine 
direct  from  the  auxiliary  steam  header.  This  reducing  valve  may 
be  placed  at  D  in  the  branches  from  the  main  header,  thereby 
keeping  the  entire  auxiliary  steam  main  at  about  3  Ib.  lower  pres- 
sure than  the  main  steam  header.  Such  a  reducing  valve  may  be  a 
heavy  cushion  check  valve  and  if  the  port  has  a  diameter  of  4  in., 
the  valve  would  weigh  about  40  Ib.,  or  the  valve  could  be  spring 
loaded,  the  same  as  a  safety  valve.  With  reducing  valves  at  the 
points  marked  D,  the  system  would  at  all  times  be  ready  for  opera- 


6o 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


LIVE  STEAM  DRIPS.  6 1 

tion.  Even  after  shutting  down,  in  case  there  should  be  one  pump 
running  very  slowly,  this  pump  would  be  able  to  take  steam  through 
the  drip  system,  and  if  the  fire  pump  should  at  any  time  be  put  into 
full  service  the  two  relief  valves  would  open  and  supply  the  auxil- 
iary main.  By  placing  the  reducing  valves  at  D  there  is  no 
danger  of  their  being  opened  and  the  pressure  run  up  on  the  drip 
system. 

The  characteristic  features  of  this  system  are  a  live  steam  main 
well  drained  to  a  low  down  drip  main,  an  auxiliary  steam  main  in- 
dependently drained  to  the  heater,  an  overhead  receiver  into  which 
drips  discharge,  a  connection  from  the  drip  receiver  to  the  auxiliary 
steam  mains,  and  a  connection  from  the  main  header  through  a 
resistance  to  the  auxiliary  steam  main,  this  resistance  preventing 
steam  from  flowing  except  when  the  auxiliary  main  pressure  and 
the  receiver  pressure  are  enough  lower  than  the  boiler  pressure  to 
overcome  the  resistance  and  allow  water  to  be  returned  to  the  boil- 
ers. In  Fig.  41  are  shown  the  receiver  drip  pumps  and  the  low 
down  auxiliary  steam  main,  which  main  is  large  and  serves  for  both 
the  drip  and  steam  mains.  This  system  is  well  drained  and  has  the 
characteristic  that  before  any  damage  could  be  done  to  the  high 
speed  or  large  units,  trouble  will  make  itself  known  by  a  cracking 
noise  of  water  in  the  steam  pumps  and  piping,  but  without  any 
liability  of  injuring  them. 

The  main  point  to  consider  in  the  disposal  of  steam  drips  is  to 
keep  them  away  from  the  large  units,  and  any  system  that  will  do 
this  under  all  circumstances,  even  though  it  causes  stoker  engines, 
pumps  and  other  auxiliaries  to  stop  during  the  flooding,  is  far  more 
preferable  than  a  system  which  would  flood  the  main  units  in  case 
the  removal  of  the  drips  be  obstructed. 

The  system  as  shown  in  Fig.  41  would  consist  primarily  of  the 
main  steam  header  and  the  auxiliary  header,  the  auxiliary  header 
being  supplied  with  steam  through  the  drip  openings  in  the  main 
engine  receivers.  The  steam  branches  to  the  auxiliaries  are  taken 
off  the  top  of  the  auxiliary  steam  main  and  drains  are  led  from  the 
bottom  of  the  auxiliary  steam  main  to  the  receiver  of  the  drip 
pumps.  Emergency  connections  should  be  made  from  the  auxiliary 
main  to  the  heater  and  to  the  blow-off  main  so  that  they  can  be 
used  in  case  the  lines  become  flooded.  This  style  of  drainage  has 
the  great  advantage  that  by  means  of  the  cracking  noise  the  auxil- 
iaries are  positive  indicators  of  the  operation  of  the  drip  system. 


62 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


LIVE  STEAM  DRIPS.  63 

The  auxiliary  main  shown  in  Fig.  41  would  necessarily  be  placed 
below  the  reheater  drain. 

The  reheater  as  ordinarily  placed  between  the  high  and  low 
pressure  cylinders  brings  into  the  station  layout  a  very  troublesome 
detail.  An  ordinary  form  of  reheater  construction  is  a  copper  pipe 
coil  with  the  inlet  and  outlet  of  the  same  size  as  the  opening  in 
the  pipe  and  by  using  a  small  size  tube  for  this  coil  of  a  very  long 
length,  a  marked  drop  in  the  pressure  as  measured  at  the  two  ends 


FIG.  42.    System;  Collecting  Steam  Drips  of  slightly  Varying  Pressures. 

of  the  coil  is  obtained.  To  drain  properly  such  a  reheater  it  is 
necessary  to  place  the  drip  main  far  enough  below  the  heater  to 
provide  a  gravity  column  which  will  make  up  for  the  pressure  lost 
in  the  reheater.  If  the  reheater  used  were  of  a  pattern  similar  to 
the  bent  U-shaped  tube  closed  heater,  there  would  be  an  ample 
area  for  steam  flow  and  therefore  no  appreciable  drop  in  the  pres- 
sure. The  receiver  should  be  placed  horizontally  and  as  high  as 
possible  so  that  the  drips  can  be  properly  taken  care  of.  If  an  auto- 
matic receiver  pump  as  illustrated  in  Fig.  41  is  to  be  used,  the  inter- 
mediate engine  receiver  must  be  kept  close  to  the  underside  of  the 
floor  as  shown  in  Fig.  42.  This  is  necessary  for  two  reasons  —  to 


64 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


give  ample  head  room  between  the  basement  floor  and  the  reheater 
drip  outlet,  and  to  provide  a  sufficient  gravity  leg,  A,  to  overcome 
the  pressure  loss  in  the  reheater.  In  case  the  boiler  room  floor  line 
is  but  a  foot  or  so  above  the  basement  floor  it  would  then  be  neces- 
sary to  place  the  automatic  pumps  in  a  pit,  instead  of  on  the  base- 
ment floor  as  shown  in  Fig.  42. 

Unfortunately  engine  builders  are  not  skilled  pipe  fitters  or  they 
would  use  better  designed  connections  between  their  high  and  low 
pressure  cylinders,  and  also  place  their  reheaters  at  a  relatively 
higher  level.  The  reheater  connection  shown  in  Fig.  43  is  a  very 


FIG.  43.   System;   Supporting  Engine  Reheaters  to  give  Sufficient  Head 
for  Drip  Flow. 


simple  arrangement  which  has  the  advantage  that  it  can  be  varied 
about  i  in.  either  way  between  the  centers  of  the  cylinder  connec- 
tions. This  variation  is  obtained  in  the  bolt  holes  at  joints  a,  b,  c, 
and  d;  if  a  is  even  three-quarter  inches  higher  or  lower  than  d,  the 
receiver  can  be  kept  level  by  sliding  the  joints  on  their  faces  at  b, 
c,  e,  /,  g,  and  h.  The  bolt  holes  should  be  one-eighth  inch  larger 
than  the  bolts.  It  is  advisable  for  the  engineer  to  arrange  this 
detail  when  the  engine  is  ordered  because  it  is  very  difficult  to 
make  a  satisfactory  drainage  system  if  a  vertical  receiver  in  the 
basement  must  be  used,  or  if  for  any  other  reason  the  receivers 
should  have  their  drain  openings  close  to  the  floor. 

The  low  down  auxiliary  steam  and  drip  main  can  be  used  with 
the  gravity  return  as  well  as  with  the  receiver  pump.  Fig.  44 
shows  such  a  main  with  a  reducing  valve  at  A.  The  pipe  lines 
for  the  drain  system  as  shown  need  be  only  of  sufficient  size  to 
handle  the  drains,  because  when  the  plant  is  running  one  fan 


LIVE  STEAM  DRIPS. 


66  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

engine  must  also  run  and  this  will  take  care  of  the  drips.  When 
the  fan  engine  is  shut  down  the  condensation  in  the  riser  pipe  will 
drop  back  into  the  auxiliary  main.  In  starting  up  the  plant,  water 
can  be  run  out  of  this  main  into  the  heater  through  the  by-pass  and 
any  section  of  the  auxiliary  main  or  drain  system  may  be  shut  down, 
and  the  drips  be  run  through  the  bleeders  either  to  the  heater  or 
the  blow-off  main.  The  steam  connections  leading  from  the  auxil- 
iary main  should  be  long  radius  fittings  and  the  main  should  be 
large  enough  to  avoid  the  lifting  of  the  condensation  lying  at  the 
bottom  of  the  line.  The  characteristic  features  of  this  system  are, 
main  steam  header,  auxiliary  steam  headers  supplied  through  drip 
openings  of  the  main  header,  auxiliary  branches  taken  off  the  top 
of  the  auxiliary  main,  connection  run  from  drip  pocket  on  the 
under  side  of  auxiliary  main  to  overhead  separator,  steam  taken 
from  this  separator  to  a  constantly  used  auxiliary,  and  another  line 
run  to  this  auxiliary  which  will  supply  it  when  the  pressure  drops 
below  the  set  amount  necessary  to  return  drips  to  the  boilers. 

The  system  shown  in  Fig.  44  is  quite  simple,  in  fact,  more  so  than 
that  shown  in  either  Fig.  40  or  41.  The  only  appliance  which  must 
constantly  be  watched  and  kept  in  good  order  is  the  reducing  valve 
and  the  operation  of  this  valve  can  easily  be  checked  by  having 
gages  on  both  sides  of  the  valve  so  that  the  difference  in  pressures 
can  be  observed.  In  case  the  return  system  fails  to  operate  prop- 
erly the  drips  will  give  warning  in  the  pump  cylinders  or  stoker 
engines.  This  is  a  very  valuable  characteristic  and  the  system 
should  be  so  laid  out  that  the  station  will  not  be  dependent  upon 
steam  traps,  bleeders  or  automatic  devices  for  this  service.  With 
these  things  in  view  let  it  be  assumed  that  Fig.  44  illustrates  the 
drip  system  for  the  proposed  station. 


CHAPTER  VI. 


BLOW-OFF  AND  EXHAUST  PIPING. 

Blow-Off  Piping.  A  blow-off  system  is  the  next  to  be  studied, 
and  although  this  may  seem  but  a  minor  matter,  if  it  is  not  properly 
laid  out  it  will  be  a  major  torment.  A  blow-off  system  is  primarily 
arranged  for  the  purpose  of  removing  the  water  and  precipitation 
from  the  lower  parts  of  the  boilers,  economizers  and  similar  parts 


s* 


0s 


a 


Le 


„,„  \  1  *-$at0tr0rfsb*A\  I  ., 

^nnrap 


FIG.  45.   Sample  System;  High  Pressure  Blow-off  Lines. 

of  the  general  system.  The  difficulties  to  be  overcome  in  a  blow- 
off  system  are  the  sudden  changes  in  temperature  with  their  atten- 
dant expansion  and  contraction  stresses,  the  providing  of  a  means 
for  liberating  the  vapors  and  reducing  the  temperature  of  the  blow- 
off  water  before  it  reaches  the  sewer,  and  finally  the  providing  for 
the  repairing  of  underground  work  which  must  be  left  free  to 
expand  and  contract.  Fig.  45  shows  a  blow-off  system  for  the 
proposed  station.  The  blow-off  cisterns  should  be  located  about 

67 


68  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

fifty  feet  from  the  building  and  the  system  should  be  operative  with 
the  use  of  one  basin  only,  because  the  other  may  be  used  for  an 
intake  as  shown  in  Fig.  22. 

The  underside  of  the  partition  and  the  bottom  of  the  cistern 
should  be  about  six  inches,  and  four  feet,  respectively,  below  the 
bottom  of  the  water  way,  with  the  blow-off  pipe  pointed  towards 
but  not  carried  into  the  water  way.  The  different  blow-off  lines 
should  be  free  to  move  longitudinally  or  transversely,  and  the  ends 
at  the  cistern  should  be  passed  through  a  metal  sleeve  which  will 
permit  free  expansion.  It  is  safe  to  say  that  a  blow-off  line  keeps 
moving  continually.  If  trouble  is  to  be  averted  the  branches  to 
the  boilers  must  be  long.  There  is  less  trouble  from  water-hammer 
in  pipes  if  the  discharge  end  is  above  the  water  line;  otherwise 
the  water  at  boiler  temperature  expands  to  steam  which  drives  the 
water  out  of  the  line,  then,  as  soon  as  the  valve  is  shut,  this  steam 
condenses  and  draws  the  water  back  into  the  pipe  in  "slugs." 
When  these  slugs  strike  the  bends  in  the  pipe  line  the  sides  of  the 
fittings  are  often  broken.  The  strains  produced  by  water-hammer 
are  wholly  distinct  and  foreign  to  the  pressure  carried  in  the  pipe, 
in  fact,  a  line  open  to  atmosphere  can  be  damaged  greatly  by  water- 
hammer.  The  writer  has  knowledge  of  a  i4-in.  exhaust  elbow, 
about  five-eighths  inch  thickness  of  metal,  which  had  its  entire 
side  broken  out  by  water-hammer,  the  strain  being  much  the  same 
as  though  a  man  had  struck  the  fitting  with  a  sledge  of  the  same 
weight  and  moving  at  the  same  velocity  as  the  water. 

If  it  is  necessary  to  place  the  end  of  the  blow-off  discharge  be- 
low the  water,  then  check  valves,  marked  A  in  Fig.  45,  should  be 
placed  in  the  line  to  break  the  vacuum  formed.  These  checks 
should  be  placed  above  the  main.  Air  cushions  could  be  used  to 
prevent  the  hammering  but  unless  they  were  placed  at  every  point 
where  the  direction  of  flow  is  changed  they  would  be  useless.  This 
method  would  be  quite  impractical  with  such  a  system  as  is  shown 
in  Fig.  34,  because  the  direction  of  flow  would  be  greatly  changed 
when  shifting  the  discharge  outlet  from  one  cistern  to  the  other. 
Check  valves  are  inexpensive  and  reduce  the  back  water  flow  very 
materially  by  filling  the  main  with  air,  thus  causing  an  air  cushion, 
and  it  is  a  good  plan  to  place  check  valves  on  the  line,  even  though 
the  main  discharges  are  above  the  water,  but  such  valves  may  be 
of  somewhat  smaller  size. 

While  washing  a  boiler  through  the  blow-off  valve,  this  valve 


BLOW-OFF   AND   EXHAUST  PIPING.  69 

must  necessarily  be  left  open.  For  this  reason,  two  blow-off  valves 
for  each  boiler  are  shown  in  Fig.  45,  and  with  this  arrangement 
the  valve  farthest  from  the  boiler  can  be  used  to  shut  off  the  main 
when  the  boiler  is  being  cleaned.  The  center  piece  of  the  valve 
close  to  the  boiler  meanwhile  can  be  removed,  thus  allowing  the 
wash-water  to  flow  to  the  sewer  instead  of  to  the  blow-off  main. 
This  arrangement  avoids  the  possibility  of  a  fireman's  blowing  off 
his  boiler  and  thus  scalding  a  boiler  cleaner  who  at  the  same  time 
may  be  working  on  the  other  boiler,  and  it  has  the  added  advan- 
tage that  by  keeping  the  wash-water  out  of  the  blow-off  line  there 
is  less  liability  of  this  line  becoming  blocked  with  scale.  In  case 
the  outer  operating  valve  leaks,  the  inner  valve  may  be  closed  and 
the  outer  valve  repaired  while  the  pressure  is  on.  Details  of  valves 
arranged  for  washout  and  also  details  of  the  blow-off  cistern  will 
be  given  later. 

The  branches  from  the  blow-off  main  to  the  boiler  must  have 
ample  length  of  pipe  in  them  to  allow  for  expansion  and  contrac- 
tion. The  blow-off  for  the  problem  station  would  be  about  175  ft. 
long  and  at  extreme  temperatures  would  differ  in  length  about  4  in., 
but  by  anchoring  this  main  at  the  center,  either  end  would  travel 
only  about  2  in.  It  is  a  very  common  practice  to  run  short,  stiff 
boiler  connections  to  the  blow-off  main.  This  is  often  a  source  of 
trouble  because  2  in.  of  movement  at  the  end  of  the  main  requires  at 
least  12  ft.  of  2^-in.  pipe  for  the  boiler  branch  in  order  to  provide 
a  safe  swing. 

It  may  be  desired  to  run  the  water  column  drains  into  a  large 
funnel  and  pipe  the  funnel  to  the  boiler  blow-off  branch,  tapping  in 
between  the  blow-off  valves  and  blow-off  main.  In  order  to  prevent 
the  blow-off  from  backing  through  the  funnel  there  should  be  a 
check  valve  in  the  pipe  leading  away  from  the  funnel.  If  the 
funnels  are  placed  at  each  boiler,  it  will  not  be  necessary  to 
provide  vacuum  breaking  checks  in  the  main  because  the  eight 
funnel  drain  checks  will  serve  the  same  purpose. 

In  blowing  off  the  economizer,  care  should  be  taken  that  the 
valves  are  operated  to  suit  the  control  of  the  feed  pump  because 
if  the  pump  is  controlled  by  feed  pressure,  time  should  be  given  it 
to  increase  in  speed  and  so,  by  opening  the  valve  slowly,  main- 
tain the  pressure  on  the  economizer.  *  Located  within  sight  of  the 
operator  of  the  economizer  blow-off  there  should  be  a  gage  with  a 
three-way  cock,  one  pressure  pipe  running  to  the  header  and  the 


/O  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

other  to  the  top  of  the  economizer.  The  operator  can  note  the 
steam  pressure,  then  throw  the  cock  to  the  economizer  pressure  and, 
while  blowing,  not  allow  the  pressure  to  drop  below  a  point  which 
will  cause  the  economizer  to  generate  steam,  which  pressure  can  be 
determined  by  observing  the  temperature  of  the  water.  This  is 
one  of  the  most  delicate  features  of  economizer  operation.  The 
feed  pump  cannot  ordinarily  supply  water  as  fast  as  it  can  be 
blown  off,  so  when  closing  the  blow-off,  the  operator  should  note  the 
pressure  and  by  closing  the  valve  slowly,  give  the  pump  time  to 
slow  down  under  its  own  control.  Closing  the  blow-off  quickly 
while  the  pump  is  working  at  high  speed  will  throw  excessive  pres- 
sures and  strains  on  the  economizer. 

The  method  of  blowing  off  an  economizer  should  be  well  under- 
stood and  carefully  followed  to  avoid  serious  losses  due  to  breaking 
economizer  tubes  or  headers.  For  instance,  let  it  be  assumed  that 
the  plant  has  been  worked  hard  and  the  feed  to  the  economizer  is 
taken  from  the  hot  well  or  small  heater,  the  gas  temperature  being 
high  and  the  economizer  very  warm.  Now,  if  the  economizer  is 
blown  off  under  these  conditions,  there  will  be  a  very  sudden  change 
of  pressure  and  a  great  possibility  of  cracking  the  economizer  tubes. 
The  correct  method  of  operation  is  to  go  down  the  line  of  boilers 
and  blow  them  off  one  by  one,  allowing  the  pump  to  run  at  a  high 
speed,  and  by  the  time  the  boilers  are  filled  again  the  economizer 
will  be  cooled  to  such  an  extent  that  the  incoming  water  will  not 
subject  it  to  very  severe  strains  and,  as  the  temperature  is  down,  the 
blow-off  can  now  be  opened,  allowing  the  economizer  pressure  to 
drop  to  a  low  point  without  making  steam.  If  steam  is  generated, 
the  condensation  of  this  steam  causes  water-hammer,  which  is 
always  productive  of  trouble  wherever  it  occurs.  An  economizer 
can  give  very  good  or  bad  results,  being  dependent  entirely  upon 
its  design,  system  of  installation  and  operation. 

The  blow-off  cisterns  should  have  a  large  open  grating  at  the 
top  to  allow  the  escape  of  steam,  and  if  this  cistern  be  close  to  or  in 
the  building,  it  should  be  supplied  with  a  very  large  pipe  to  carry 
off  the  steam.  The  sewer  connection  should  have  a  deep  water  seal 
to  prevent  steam  from  blowing  into  the  sewer.  Water  leaving  the 
boilers  at  ioo-lb.  pressure  will  vaporize  i  Ib.  out  of  every  7.5  Ib. 
blown  off.  This  makes  3.5  cu.  ft.  of  steam  for  each  pound  of  blow- 
off  water,  or  219  times  as  much  volume  of  steam  passing  out  of 
the  top  of  the  blow-off  cistern  as  there  is  water  passing  through  the 


BLOW-OFF   AND   EXHAUST  PIPING.  /I 

sewer.  During  a  blow-off  period  there  will  not  ordinarily  be  blown 
off  more  than  75  Ib.  of  water  per  second  and  10  Ib.  of  this  will  be 
in  the  form  of  steam.  The  atmospheric  exhausts  for  engines  are 
generally  arranged  with  a  capacity  of  about  4  Ib.  per  second  per 
square  foot  of  sectional  area.  This  requires  a  vent  pipe  having  not 
less  than  2.5  sq.  ft.  cross  sectional  area  for  an  engine,  but  since  this 
flow  is  steady,  we  can  make  the  pipe  of  about  1.25  sq.  ft.  cross  sec- 
tional area,  or  the  diameter  of  the  vent  pipe  would  be  approximately 
1 6  in.  In  case  the  blow-off  cistern  is  very  large,  the  water  in  it 
may  then  have  time  to  cool  and  so  there  will  not  be  as  much  vapor 
as  just  stated.  This,  however,  would  help  matters  only  a  portion 
of  the  time,  because,  when  a  second  boiler  is  being  blown  off, 
immediately  following  the  first,  the  blow-off  will  meet  water  which 
is  of  such  a  temperature  that  it  will  not  take  up  any  heat  without 
vaporizing  and  then  the  full  amount  of  vapor  will  be  formed.  The 
chief  object  in  retaining  the  water  in  the  cistern  is  to  break  up  the 
force  of  the  discharge  and  thus  avoid  cutting  a  hole  in  the  cistern 
by  the  disintegrating  action  of  the  water  of  high  temperature  being 
directed  at  one  point. 

It  may  be  found  desirable  to  provide  for  taking  care  of  still  other 
drains  in  preference  to  discharging  them  into  the  sewer,  such  as  the 
high  temperature  low-pressure  drips  from  exhaust  lines,  inter- 
mediate receiver  drips,  heater  overflow,  washout  for  oil  tanks,  etc. 
Since  these  drains  are  located  at  low  level,  it  would  hardly  be 
possible  to  keep  them  above  the  floor  without  their  becoming  an 
obstruction  in  the  engine  room.  These  lines  should  be  made  of 
heavy  cast  iron  soil  pipe  with  the  joints  well  calked  and  laid  in  and 
filled  around  with  sand  so  that  expansion  and  contraction  may 
take  place  freely  without  damaging  the  calked  joints. 

A  mixed  system  for  taking  care  of  these  other  drips  is  shown 
in  Fig.  46;  line  A  takes  receiver  drips,  also  exhausts  drips  and 
oil  washout.  No  catch  basins  are  connected  to  this  line  because 
the  question  of  expansion  and  contraction  would  be  difficult  to 
arrange  for  where  the  lines  enter  the  basins.  The  line  and  branches 
are  of  iron  pipe,  calked,  and  since  there  would  be  considerable 
vapor  if  any  connections  were  left  open,  the  entire  line  is  made 
tight  and  the  discharge  is  dropped  into  a  sump  at  the  bottom  of 
the  waste  water  way.  The  elbows  of  this  line  should  be  arranged 
as  shown  in  Fig.  46,  so  that  they  may  expand  without  trouble  at  the 
joints  or  at  the  floor.  Line  B  is  a  regular  floor  drain  and  may  be 


72  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

of  sewer  tile  and  arranged  to  discharge  into  the  waste  water  way, 
Line  C  is  of  cast  iron  pipe  but,  as  it  is  not  subjected  to  very  high 
temperatures,  about  170  degrees  at  the  most,  the  catch  basin  and 
drain  connections  are  made  into  this  line.  Very  little  oil  passes 
through  this  line  and  a  loose  joint  is  not  a  serious  matter.  There 
is  no  essential  reason  for  duplicating  or  cross  connecting  this  class 


FIG.  46.   Sample  System;  Low  Pressure  Blow-off  Lines. 

of  mains,  not  because  they  are  unimportant,  but  because  they  are 
not  under  pressure  and  so  can  be  discharged  directly  on  the  engine 
room  floor  until  any  necessary  repair  is  made.  Wherever  possible, 
an  open  gutter  should  be  run  alongside  of  the  wall,  because  such 
drains  can  easily  be  cleaned  without  interfering  in  the  least  with 
operation.  The  details  of  such  a  gutter  will  be  shown  later. 

Exhaust  Piping.  The  next  division  of  the  subject  which  will 
be  taken  up  is  that  describing  the  main  engine  exhaust  lines.  In 
Fig.  10  is  shown  the  general  arrangement  of  the  proposed  station. 
The  arrangement  of  the  condensers  is  illustrated  by  Fig.  22.  The 
problem  now  in  hand  is  the  carrying  away  of  the  exhaust  steam 


BLOW-OFF  AND   EXHAUST  PIPING.  73 

for  six  engines  and  two  condensers,  realizing  that  there  must 
always  be  in  operation  three  large  engines,  one  condenser  and  one 
exciter  engine. 

An  arrangement  of  the  exhaust  piping  which  meets  the  condi- 
tions of  the  problem  is  illustrated  in  Fig.  47.  These  connections 
permit  the  repairing  of  any  portion  of  the  vacuum  main  or  branches 
without  necessitating  the  shutting  down  of  more  than  one  large 


FIG.  47.   System;  Engine  Exhaust  to  Condensers  and  Exhaust  Main  with  Unde- 
sirable Features. 

unit,  and  always  allowing  one  exciter  engine  to  be  run.  The 
atmospheric  exhaust  main  is  shown  on  the  drawing  by  dotted  lines, 
and  would  not  ordinarily  be  used.  The  use  of  one  large  exhaust 
main  for  regular  operation  of  several  engines  is  not  as  economical 
in  first  cost,  nor  as  safe  to  operate,  as  individual  atmospheric 
exhaust  lines.  A  method  of  laying  out  a  large  atmospheric  main, 
which  would  be  accessible  for  repairs  at  all  times,  and  which  would 
neither  furnish  a  chance  for  the  engine  to  lose  its  vacuum  nor 
injure  a  man  by  exhausting  onto  him,  is  illustrated  in  Fig.  48. 
If  the  connections  were  all  led  into  the  large  main  without  pro- 
vision being  made  for  dividing  this  main  into  sections,  the  prob- 
abilities are  that  in  case  of  repairs  being  necessary  on  the  main 
branches  or  atmospheric  valves,  a  shutdown  would  be  necessary, 
but  if  the  main  is  designed  with  the  proper  allowance  for  expansion 
and  well  built  of  amply  heavy  materials,  there  would  undoubtedly 
no  trouble  arise  which  could  not  be  remedied  before  the  vacuum 


74 


STEAM   POWER  PLANT  PIPING   SYSTEMS. 


was  affected.  However,  as  the  idea  from  the  first  has  been  that  a 
station  should  be  designed  so  that  any  portion  of  it  might  be  shut 
down  for  several  days,  if  necessary,  and  the  rest  of  the  machinery 
care  for  the  regular  operation,  let  this  idea  still  remain  foremost. 
Then  Fig.  48  is  the  best  piping  system  for  the  exhaue  t  mains,  and 
if  desired  the  condensers  may  be  located  in  the  center  of  the  station 
as  shown  in  this  figure.  The  general  piping  system  illustrated  in 
Figs.  47  and  48  is  the  same,  these  figures  differing  only  in  the  loca- 
tion of  the  lines.  The  curved  piping  as  shown  in  Fig.  48  should 


FIG.  48.   Sample  System;   Engine  Exhaust  to  Condensers  and  Exhaust  Main  with 
Undesirable  Features. 

never  be  used  if  there  is  the  least  possibility  of  additions  ever  being 
made  to  the  station.  A  better  method  would  be  to  finish  the  ends 
of  all  lines  running  lengthwise  of  the  plant  with  T's  having  blind 
flanges  ready  for  future  additions.  Such  a  modification  is  shown 
by  the  dotted  lines  in  Fig.  48. 

The  next  subject  to  be  considered  is  the  exhaust  piping  for  the 
auxiliary  machinery.  It  is  not  unusual  to  find  the  auxiliaries  piped 
with  double  connections,  so  that  they  may  be  run  either  condensing 
or  non-condensing,  and  exciter  engines  are  also  arranged  so  that 
they  may  be  connected  to  the  heater.  Such  systems  are  never 
flexible  or  economical.  Consider,  for  instance,  the  proposed 
station:  The  auxiliaries  in  this  station  are  the  steam  pumps,  two 
of  which  are  required  to  do  quite  light  work,  an  air  pump  which 
uses  steam  economically,  and  the  compound  fan  engines,  which  are 


SLOW-OFF   AND   EXHAUST  PIPING.  J '$ 

also  economical  machines.  The  heaters  taking  steam  from  these 
auxiliaries  will,  by  taking  water  from  the  hot  well  at  about  95  degrees, 
raise  its  temperature  to  170  or  180  degrees.  In  this  station,  in  addi- 
tion to  exciting  the  main  generators,  the  exciter  unit  would  be  called 
upon  to  furnish  current  for  all  the  electrical  requirements  of  the 
station,  such  as  lighting  system,  circulating  pump,  motors,  air 
compressor,  blast  fan  for  transformers,  crane,  coal  handling  machin- 
ery and  for  motor  driven  tools  in  the  adjacent  shop.  Thus  it  is 
seen  that  the  exciter  engine  would  carry  more  load  and  so  deliver 
more  exhaust  steam  than  the  heater  could  condense,  which  would 
allow  much  of  the  steam  to  waste  to  atmosphere.  This  plant  will 
use  economizers,  and  so  there  will  not  be  much  advantage  in 
delivering  high  temperature  water  from  the  heaters  to  the  econo- 
mizers, because  the  economizers  will  raise  water  more  degrees  in 
temperature  when  receiving  low  temperature  water  than  when 
receiving  water  of  high  temperature.  In  other  words,  the  capacity 
and  utility  of  an  economizer  diminishes  as  the  temperature  of  its 
feed  water  is  increased,  and  the  greater  amount  of  work  asked  for 
from  the  economizer  the  better  paying  investment  it  will  be.  An 
active  circulation  is  not  provided  for  in  the  general  design  of 
economizers  on  account  of  practical  difficulties,  and  as  actual  experi- 
ment has  demonstrated  that  twice  as  much  heat  is  delivered  to 
water  circulating  at  the  rate  of  3  ft.  per  second  as  is  delivered  to  it 
without  circulation,  it  may  be  seen  that  the  commercial  value  of 
an  economizer  would  be  increased  greatly  if  the  advantages  of  free 
circulation  were  provided  for. 

If  the  plant  were  supplied  with  economizers  it  would  be  an 
economical  plan  to  deliver  all  the  steam  to  the  heater  that  it  would 
condense,  exhausting  such  machines  as  are  economical  in  the  use 
of  steam  into  the  condensers  and  such  machines  as  are  wasteful 
into  the  heater.  A  system  for  connecting  certain  machines  and 
allowing  them  to  be  run  in  either  of  the  ways  just  mentioned  is 
shown  in  Fig.  49.  This  system  is  flexible  only  in  regard  to  opera- 
tion and  should  not  be  used  for  any  lines  which  are  at  all  times 
essential  for  the  continued  operation  of  the  station.  A  portion  of 
the  line  marked  A  is  indispensable,  and  late  at  night,  when  the 
pumps  may  be  shut  down,  the  exciter  engines  would  be  running  non- 
condensing,  and  this  part  of  the  line  would  then  be  used  by  the 
exciter  engines. 

Another  point  to  consider,  which  may  be  stated  as  one  of  the 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


more  important  details  in  laying  out  station  systems,  is  the  ability 
to  be  able  to  take  apart  any  valve  in  the  station,  not  only  for  repairs 
needing  immediate  attention,  but  for  general  repairs  when  the  load 
is  light  and  not  over  one-half  the  station  capacity  is  called  for. 
To  be  able  to  shut  off  one  section  of  the  piping  is  only  a  partial 

solution  of  the  problem  of  designing  a 
correct  system;  it  must  be  possible  to 
shut  off  the  shut-off  itself.  Figure  48 
shows  numerous  valves,  any  one  of 
which  can  be  taken  out  of  the  line  or 
have  repairs  made  on  it  and  the  con- 
.tinued  operation  of  the  other  half  of  the 
station  be  possible. 

Referring  to  Fig.  47  it  is  seen  that 
there  are  two  atmospheric  valves  open- 
ing into  one  pipe,  and  if  one  valve  is 
being  repaired  there  is  a  constant  dan- 
ger of  losing  the  vacuum  and  exhaust 
from  the  other  engine  reaching  the 
valve.  This  is  not  a  good  system,  be- 
FIG.  49..  System;  Exhaust  from  c'  each  atmospheric  branch  should 

Auxiliaries,  Improperly  Laid 

Out.  run  independently  to  the  atmosphere, 

or  have  a  valve  in  it. 

There  is  nothing  unusual  in  the  appearance  of  the  connection 
shown  in  Fig.  49,  such  an  arrangement  being  very  ordinary.  The 
designer  of  a  piping  system  must  not  be  contented  with  laying  out 
a  system  which  looks  all  right,  but  he  should  analyze  every  require- 
ment and  see  that  his  design  conforms  with  an  established  plan. 

Referring  to  Fig.  49  it  may  be  seen  that  in  order  to  do  any 
work  at  all  upon  the  valve  shutting  off  the  main  from  the  branches, 
it  will  be  necessary  to  shut  down  the  entire  auxiliary  exhaust  main. 
Such  a  design  is  not  a  system,  but  is  the  very  limit  of  crudeness. 

The  auxiliary  exhaust  main  should  therefore  be  next  laid  out 
with  a  view  to  making  repairs  to  the  pipe  line  possible  and  still 
allow  the  operation  of  three-fourths  of  the  entire  plant,  or  permit 
any  valve  to  be  removed  and  allow  the  operation  of  one-half  the 
plant. 

It  should  be  understood  that  if  a  valve  blows  a  gasket  or  springs 
a  bad  leak  between  the  bonnet  and  the  body,  it  is  yet  possible 
to  close  the  valve  and  operate  three-fourths  of  the  capacity  of  the 


BLOW-OFF   AND    EXHAUST  PIPING. 


77 


plant  until  such  time  as  the  load  can  be  carried  by  half  the 
machines  and  the  repairs  be  made. 

A  List  of  the  machinery  which  must  be  piped  to  the  heater  and 
atmosphere  comprises  two  dry  vacuum  pumps,  two  feed  pumps, 


D 


HH 


FIG.  50.    System;  Exhaust  from  Auxiliaries,  Properly  Laid  Out. 

one  fire  pump  and  two  fan  -engines.  These  machines  are  shown 
in  Fig.  50,  together  with  the  properly  located  back  pressure 
valves  and  atmospheric  stand- 
pipes  at  the 
exhaust  main. 


ends  of  the 
In  case  of 
accidents  to  valves  a  and  &, 
repairs  would  be  found  diffi- 
cult, because  it  would  be 
necessary  to  operate  with  but 
one  pump.  This,  however,  is 
possible,  and  as  there  is  low 
duty  on  the  shut-off  valves, 
further  protection  is  not 
justified.  It  is  necessary  that 
the  exhaust  main  should  be 
pitched  toward  the  heater  so 
that  all  condensation  will 
flow  in  that  direction  and  it 


/Arf 


-D 


FIG.  51.   System;  Same  as  50,  Modified 
Position  of  Parts. 


will  then  be  possible  to  run  the  steam  drip  bleeders  into  the 
exhaust  main,  thus  saving  both  the  distilled  water  and  the  heat 
units. 


78  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

The  lines  may  be  located  in  various  positions  and  yet  preserve 
the  system  shown  in  Fig.  51.  For  instance,  Fig.  50  shows  a  dif- 
ferent arrangement  of  the  machines,  valves,  etc.,  but  the  general 
system  is  unchanged.  In  Fig.  50  the  atmospheric  valves  are 
located  near  the  heater  so  that  the  air  vent  of  the  heater  may  easily 
be  run  into  these  pipes.  The  general  arrangement  of  the  pipe  lines 


s/r/v 

T3- 


J        I 


•D 


FIG.  52.    Sample  System;  Exhaust  from  Auxiliaries  to  Heater. 

must  necessarily  adapt  itself  to  local  conditions,  but  the  lines  should 
be  so  run  that  the  original  system  will  be  preserved. 

The  general  rearrangement  of  the  auxiliary  steam  and  exhaust 
mains  when  laid  out  on  the  loop  plan  is  shown  in  Fig.  52.  This 
plan  permits  the  shutting  down  of  the  heater,  atmospheric  pipe, 
or  any  portion  of  the  lines,  and  yet  three-fourths  of  the  plant 
remains  in  operation. 


CHAPTER    VII. 
AIR  AND  OILING  SYSTEMS. 

Compressed  Air  System.  Compressed  air  is  now  considered 
essential  in  the  operation  of  modern  power  stations  and  is  chiefly 
used  for  cleaning  electrical  machinery  and  apparatus;  it  is  also 
used  for  other  purposes  in  the  plant  because  it  is  available. 
Compressed  air  service  for  cleaning  purposes  is  not  vital  in  the 
operation  of  the  station,  and  therefore  can  be  laid  out  on  a  single 
main,  systemless  plan,  but  of  course  when  the  air  system  is  so 
designed,  there  should  be  no  vital  system  dependent  upon  air 
pressure  for  its  operation  unless  such  system  has  another  means 
of  supply. 

Ordinarily  it  is  not  necessary  to  use  a  large  air  compressor  nor 
large  lines,  but  in  order  to  insure  an  even  pressure  the  system 
should  have  a  storage  air  tank  of  fairly  large  capacity  from  which, 
when  needed,  a  relatively  large  volume  of  air  can  be  drawn  for  a 
short  time.  The  general  arrangement  of  such  a  system  is  shown 
in  Fig.  53.^ 

The  piping  should  be  arranged  so  that  the  compressor,  air  main 
and  branches  will  drain  into  the  air  tank.  This  tank  should  be 
provided  with  a  blow-off  through  which  condensation  can  be  dis- 
posed of.  The  compressor,  controller,  gage,  relief  and  stop  valve 
should  be  located  on  the  engine  room  floor,  and  the  tank  on  tfre 
basement  floor  with  the  air  supply  main  led  off  from  the  top.  Hose 
valves  should  be  placed  at  the  different  generators,  motors,  trans- 
formers, switchboards,  oil  switches,  etc.,  so  that  25  ft.  of  hose  will 
.reach  any  piece  of  electrical  apparatus.  If  there  is  an  oil  room 
where  inflammable  stock  is  kept  it  is  desirable  to  connect  the  air 
main  to  a  can  of  dry  fire  extinguishing  powder  in  such  a  manner 
that  by  opening  an  air  valve  the  pressure  from  the  main  will 
blow  this  powder  forcibly  into  the  room. 

Cylinder  Lubrication.  In  designing  an  oiling  system,  facilities 
must  first  be  provided  for  receiving  the  oil  in  barrels,  emptying 
the  barrels  and  disposing  of  them.  If  compound  engines  are  used 

79 


8o 


STEAM  POWER   PLANT  PIPING  SYSTEMS. 


in  the  station,  the  cylinder  lubrication  will  require  two  kinds  of 
oil.  There  will  also  be  needed  a  different  cylinder  oil  for  the 
dry  vacuum  pump  and  the  air  compressor.  Engine  or  journal  oil 
is  usually  the  same  for  the  entire  plant,  the  plan  being  to  filter  this 
oil  and  use  it  repeatedly.  Grease  will  also  be  required  for  some 


FIG.  53.    Sample  System;  Compressed  Air. 

of  the  bearings,  pins,  etc.  There  are  some  specific  requirements 
in  the  handling  of  these  materials  that  to  a  considerable  extent 
determine  the  location  of  the  different  parts  of  an  oiling  system: 

1.  The  oil  barrels  must  be  stored  in  a  cool  and  preferably  damp 
place  to  avoid  leakage. 

2.  The  oil  and  grease  stocks  must  be  separated  from  other 
p6rtions  of  the  building  in  a  fire-proof  manner  and  arrangements 
made  so  that  a  fire  in  the  oil  room  can  be  subdued  and  not  endan- 
ger the  station. 

3.  The  oil  room  must  be  accessible  from  the  outside,  in  order 
that  the  barrels  may  be  received  and  discharged. 

4.  All  the  drip  lines  and  the  drip  receiving  tank  must  be  located 
in  a  warm  place  so  that  the  drips  will  flow  freely. 

5.  Gravity  tanks  should  be  located  in  a  place  which  will  be  cool 
in  the  summer  but  warm  in  the  winter;  and  warmer  in  winter  than 
in  the  summer,  so  that  at  all  times  the  oil  will  be  of  a  temperature 
that  will  insure  free  flowing  and  render  it  easily  handled. 


AIR   AND   OILING   SYSTEMS. 


81 


6.  Cylinder  oil  and  grease  should  be  kept  so  that  the  amounts 
used  can  be  charged  to  the  respective  shifts  using  them. 

There  are  numerous  methods  of  handling  oil  and  various  systems 
that  can  be  used  in  supplying  it  to  the  machines.  Cylinder  and 
journal  oils  should  be  considered  from  different  standpoints,  when 
planning  an  oiling  system;  journal  oil  is  fed  onto  the  bearings  in  a 
much  greater  quantity  than  actually  required,  the  loss  being  not 
appreciable  because  the  drips  are  collected  and  returned  to  the 
receiving  tank.  The  object  of  piping  oil  to  bearings  is  to  insure 
complete  lubrication;  the  lubrication  of  the  cylinders  is  an  entirely 


sJP 


FIG.  54.    System;  Feeding  Cylinder  Oil  from  Tank  to  Engine. 

different  proposition.  Instead  of  providing  facilities  for  feeding  an 
excess  of  oil  into  the  cylinder,  the  contrary  should  be  done,  that  is, 
plan  the  system  so  that  it  will  require  the  least  possible  amount  of 
cylinder  oil. 

One  of  the  methods  for  placing  cylinder  oil  under  pressure  and 
delivering  it  to  the  steam  machinery  which  is  to  be  lubricated  is 
illustrated  in  Fig.  54.  The  necessary  pressure  is  maintained  here 
by  adding  to  the  steam  pressure  the  weight  of  the  water  in  a  con- 
densation pipe  connecting  the  steam  main  with  the  supply  tanks. 
The  principle  employed  is  the  same  as  that  of  the  standard  sight 
feed  lubricator  so  commonly  used. 

Two  tanks  are  used,  so  arranged  that  one  may  be  shut  off  from 
the  system  while  being  filled  from  the  supply  barrel  and  the  other 
continue  to  furnish  oil  for  the  lubricating  system.  This  equipment 
and  piping  system  is  the  equal  of  the  majority  of  installations. 


82 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


The  most  serious  objection  to  it  is  that  the  piping  is  arranged  with- 
out regard  to  any  definite  system. 

When  this  system  (Fig.  54)  is  arranged  so  that  repairs  may  be 
made  without  shutting  down  the  entire  oiling  system,  it  assumes 
the  form  shown  in  Fig.  55.  For  such  small,  inexpensive  lines  as  go 
to  make  up  an  oiling  system  it  is  good  policy  to  make  even  greater 
provision  for  repairs  than  in  the  larger  and  more  expensive  lines. 


FIG.  55.   System;  As  shown  54,  Applied  Systematically  in  a  Plant. 

If  line  valves  are  placed  at  the  points  marked  a  in  Fig.  55,  con- 
tinued operation  is  more  readily  insured.  The  cost  of  such  valves 
would  be  slight. 

When  the  style  of  lubrication  shown  in  Fig.  55  is  to  be  used  with 
high  pressure  cylinders,  it  would  be  a  good  plan  to  use  it  on  the 
low  pressure  cylinders  also,  but  the  pressure  should  not  be  as 
high  on  the  low  pressure  cylinder  oil  supply.  If  city  water  at  about 
40  Ib.  pressure  is  available,  this  can  be  used  instead  of  the  con- 
densation columns  shown  in  Fig.  55.  Air  pressure  could  also  be 
used,  but  since  the  compressed  air  system  has  not  been  designed 
with  a  view  for  continuous  operation,  its  use  with  the  oiling  system 
would  be  unsafe  unless  two  air  compressors  are  in  use  and  arranged 
independently  to  maintain  the  required  pressure.  A  low  pressure 
cylinder  oiling  system  which  can  easily  be  repaired  is  illustrated 


AIR   AND   OILING   SYSTEMS.  .  83 

in  Fig.  56.  In  this  figure  the  air  compressors  are  shown  connected 
in  a  safe  manner. 

There  are  various  pipe  systems  for  feeding  cylinder  oil,  but  the 
general  proposition  is  subject  to  many  objections,  regardless  of  the 
equipment  used. 

There  are  two  styles  of  feeders  used  to  deliver  oil  to  an  engine. 
The  older  method  is  to  use  a  sight-feed  glass  filled  with  water  and 
allow  the  drops  of  oil  to  feed  up  through  the  water.  A  drop  of 


FIG.  56.    System;  Oiling  Journals  by  Using  Tanks  and  Compressed  Air.       • 

oil  may  seem  small  in  itself,  but  it  is  an  extremely  large  quantity 
when  considered  from  a  lubrication  standpoint.  An  engine  that  is 
receiving  one  drop  a  minute  would  make,  in  the  case  of  stoker  or 
similar  engines,  possibly  250  or  300  revolutions  without  oil  to  one 
with  oil.  The  size  of  the  drop  is  not  controllable  by  the  operator. 
But  if  such  a  drop  could  be  divided  into  10  or  more  small  drops 
it  would  be  possible  to  obtain  more  economical  results  in  lubricat- 
ing with  sight  feed  lubricators.  This,  then,  is  the  weak  point  of 
all  drop  sight  feed  lubricators,  that  they  seem  to  be  feeding  too  little 
or  not  at  all  when  in  reality  they  are  feeding  too  much. 

The  best  system  for  handling  cylinder  oil  is  unquestionably  one 
which  will  give  the  greatest  amount  of  lubrication  for  the  least 
cost,  and  in  considering  cost  both  labor  and  oil  must  be  included. 
Systems  for  feeding  cylinder  oil  have  so  reduced  the  labor  cost  of 
handling  the  oil  that  they  have  made  it  possible  and  to  a  consid- 


84 


STEAM  POWER  PLANT  PIPING   SYSTEMS. 


erable  extent  excusable  to  waste  oil.  Each  operator  in  his  shift  is 
relieved  of  about  ten  cents'  worth  of  labor  and  enabled  to  waste 
one  dollar's  worth  of  oil.  Such  being  the  case,  instead  of  spending 
money  to  make  such  installations,  it  would  be  better  to  spend  money 
to  avoid  their  use;  however,  some  people  think  a  plant  must  be 
automatic  to  be  modern. 

Another  method  of  supplying  cylinder  oil  to  sight  feed  lubricators 
is  illustrated  in  Fig.  57.     This  system  uses  a  pump  to  force  oil  into 


E 

•H 

v/*™ 

<7//i 

» 

r 

c—  ,„„  ^..-^  _ 

LJ^  I — I 

FIG.  57.   System;  Oiling  Journals  by  Using  Pump  and  Governor. 

the  pressure  line  and  controls  this  pressure  with  the  pump  governor, 
the  storage  tank  being  placed  higher  than  the  pump  so  that  the  oil 
will  flow  by  gravity  from  the  tanks  to  the  pump  suction.  Much 
difficulty  is  experienced  in  lifting  cylinder  oil  in  a  pump  suction, 
and  in  fact  no  suction  for  any  service  should  be  arranged  except  by 
the  gravity  method  if  the  machinery  is  slow  running.  The  system 
shown  in  Fig.  57  to  be  complete  must  be  laid  out  on  the  loop  plan 
with  duplicate  sets  of  pumps,  distribution  lines  and  storage  tanks. 
Ordinarily  this  loop  could  be  easily  arranged  by  running  one  line 
through  the  engine  room  to  supply  all  the  steam  machines  there, 
and  the  other  line  through  the  boiler  room  to  supply  all  its 
machinery. 

The  fact  must  be  remembered  that  the  piping  system  alone  will 
not  insure  satisfactory  operation.  It  is  the  entire  system  or  method 
that  determines  the  degree  of  success.  For  instance,  Figs.  55  and 
57  are  both  good  pipe  systems,  but  each  has  objectional  features, 


AIR   AND   OILING  SYSTEMS.  85 

common  to  all  cylinder  oil  piping  systems  that  are  not  commercially 
successful.  Fig.  55  is  mechanically  a  success,  since  it  maintains 
a  steady  pressure  on  the  oil  a  fixed  amount  in  excess  of  the  steam 
pressure,  this  being  accomplished  by  the  condensation  column. 
This  steady  pressure  is  absolutely  essential  for  securing  the  best 
economy  in  drop  feeding,  which  feeding  at  its  best  is  not  the  most 
economical. 

In  the  system  shown  in  Fig.  57  the  speed  of  the  pressure  pumps 
is  regulated  by  governors  actuated  by  the  pressure  on  the  oil  end 
of  the  pumps.  This  type  of  regulator  must  be  constructed  with 
a  metallic  diaphragm,  as  oil  comes  in  contact  with  it.  Continued 
service  will  eventually  dish  any  metallic  diaphragm,  and  when  this 
has  occurred  considerable  force  is  required  to  pass  the  dish  from 
one  side  of  the  diaphragm  to  the  other.  If  such  is  the  case  in  an 
oiling  system  having  recording  pressure  charts  on  both  steam  and 
oil  lines,  sudden  changes  of  pressure  will  be  noticed  and  at  times 
the  oil  pressure  will  show  even  lower  than  the  steam  pressure  unless 
the  governor  is  loaded  down,  in  which  event  the  steam  pressure  may 
be  1 60  Ib.  and  the  oil  pressure  161  lb.,  then  due  to  the  snapping  over 
of  the  dish  in  the  diaphragm  a  pressure  4  lb.  higher  than  that  for 
which  governor  valve  was  set  will  be  needed  to  close  it.  Thus  if 
the  oil  pressure  is  set  at  5  lb.  above  that  of  the  steam  the  defect 
in  the  diaphragm  will  allow  the  oil  pressure  to  run  9  lb.  higher  than 
the  steam  pressure  before  the  governor  valve  closes.  In  other 
words,  the  head  on  the  oil  may  be  increased  or  decreased  nine  times 
and  thus  cause  such  a  change  in  the  volume  of  the  feed  that  three 
times  as  much  oil  will  be  fed  at  one  time  as  another.  With  such  a 
governor  it  is  probable  that  twice  as  much  oil  will  be  used  as  would 
be  with  the  system  shown  in  Fig.  55. 

If  it  is  wished  to  secure  greater  economy  in  the  use  of  oil  the 
sight  feed  method  must  be  discarded  for  some  other. 

The  most  common  method  for  reducing  this  waste  is  by  the  use 
of  a  force-feed  lubricator  directly  connected  to  the  moving  mechan- 
ism of  the  engine  or  pump  which  is  to  be  lubricated.  With  this 
type  of  oiling  system  the  discharge  flow  can  be  set  for  five  or  ten 
feeds  each  minute  and  the  total  of  the  ten  discharges  can  be  gaged 
for  less  than  one  drop.  Such  a  system  enables  the  lubrication  of 
each  piece  of  apparatus  to  be  carried  on  independently  and  any 
draft  of  cool  air  can  have  no  effect  upon  the  volume  of  the  feed 
as  is  the  case  with  sight-feed  lubrication. 


86  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

The  force-feed  lubricators  are  ordinarily  supplied  with  oil  by 
hand;  in  fact,  this  method  has  been  demonstrated  to  be  the  more 
economical  and  the  labor  of  filling  pumps  is  too  slight  to  be  con- 
sidered seriously.  An  important  consideration  is  the  saving  in 
the  quantity  of  oil  used ;  as  killed  operator  can  more  than  save  the 
difference  between  his  wages  and  that  of  an  inferior  man  by  the 
difference  in  the  amount  of  oil  used  alone. 

It  is  due  to  this  fact  that  the  power  station  should  be  provided 
with  a  means  for  carefully  recording  the  amounts  of  oil  used  by 
the  different  shifts.  The  systems  shown  in  Fig.  55  and  Fig.  57  are 
not  designed  for  this  purpose. 

If  a  record  is  to  be  kept  it  may  be  found  necessary  to  give  out 
oil  to  each  of  two  men  in  a  shift,  one  part  to  be  used  in  the  boiler 
room,  the  other  part  in  the  engine  room.  The  pump  supply  on 
each  part  of  the  force-feed  oiling  system  should  be  marked  with  a 
line  designating  the  point  on  the  reservoir  to  which  each  shift  must 
fill,  and  the  oil  used  in  this  filling  should  be  taken  from  a  supply 
can  charged  to  the  proper  shift.  A  great  deal  of  oil  is  wasted  in 
the  lubrication  of  the  auxiliary  machinery,  which  should  require 
but  very  little  cylinder  oil. 

If  it  is  found  desirable  to  pump  oil  from  a  storage  reservoir  to 
the  force-feed  pumps  on  the  units  which  are  to  be  lubricated,  this 
could  be  done  with  the  piping  system  shown  in  Fig.  58.  With  this 
arrangement  it  is  not  necessary  that  duplicate  receiving  tanks  be 
used.  The  air  line  may  have  its  pressure  maintained  by  a  single 
compressor  because  the  use  of  this  supply  arrangement  would  not  be 
essential  for  the  operation  of  the  engine,  since  the  pumps  could  be 
filled  at  opportune  times  and  each  shift  would  have  recorded  against 
it  the  meter  readings  showing  the  amount  of  oil  drawn  at  the  start 
and  finish  of  its  run.  If  a  separate  record  is  to  be  kept  of  the 
amount  of  oil  used  in  the  boiler  room,  this  can  be  drawn  from  a 
supply  can  whose  contents  have  been  charged  to  that  part  of  the 
station  when  withdrawn  from  the  receiving  tank  in  the  stock  room. 

In  Fig.  58  the  tap  A  is  added  for  filling  hand  oilers,  etc.  With 
this  system  there  would  be  two  complete  piping  arrangements,  one 
for  supplying  oil  to  the  high  pressure  and  one  to  the  low  pressure 
cylinders.  The  advantages  to  be  gained  by  using  two  kinds  of 
cylinder  oils  with  compound  engines  are  too  well  known  both  by 
the  oil  manufacturers  and  the  operators  to  require  giving  any 
special  reasons  for  their  use. 


AIR  AND   OILING  SYSTEMS. 


The  installation  of  a  meter  in  the  oil  supply  line  as  shown  in 
Fig.  58  allows  a  possibility  of  this  method  being  manipulated  by 
the  operators.  The  oil  pumps  on  the  engine  are  not  ordinarily 
arranged  to  be  put  under  pressure  and  with  the  system  in  Fig.  58 
the  proper  method  of  operation  would  be  to  open  the  supply  valve 
and  fill  the  pump  supply  to  the  limiting  point  which  was  earlier 
described,  and  then  close  the  shut-off  valve  tightly.  But  in  all 
probability  a  dishonest  operator  would  soon  learn  that  by  leaving 


&0O/V 

/-^ggy/vTSf/i//- 


FIG.  58.    System;  Measuring  Daily  Consumption  of  Cylinder  Oil. 

the  filler  valves  slightly  open  the  pumps  would  still  be  kept  filled 
by  a  slight  leakage  which  would  be  so  small  in  amount  that  the 
meter  'would  not  record  it.  This  would  result  in  the  showing  of 
"good  performance"  purely  by  trickery,  because  the  dishonest  oper- 
ators could  reduce  the  apparent  reading  of  the  meter  as  much  as 
they  felt  sure  would  not  arouse  suspicion. 

If  oil  is  to  be  measured  and  piped  a  better  method  is  afforded 
by  the  use  of  gage  glasses  and  graduation  on  the  tank,  thus  dis- 
pensing with  the  meter.  A  tank  30  in.  in  diameter  holds  3  gallons 
for  each  added  inch  in  height  and  as  the  error  of  reading  should  be 
within  the  limits  of  one-eighth  of  a  gallon,  which  with  a  3o-in.  tank 
means  a  difference  of  ^  in.  on  the  scale,  this  would  seem  too  close 
reading  to  be  gaged  accurately.  The  reading  should  not  be  finer 
than  about  y\  in.  to  the  pint.  This  fixes  the  diameter  of  the 
tank  at  22  in.  and  with  such  a  diameter  and  a  length  of  40  in.  its 
capacity  would  be  equal  to  one  barrel.  This  tank  would  hold 
i^  gallons  per  inch  of  its  height. 


88  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

In  the  problem  plant  which  is  being  laid  out  it  will  be  found  best 
to  use  the  piping  system  shown  in  Fig.  58  with  the  22-in.  stock 
tank,  gage  glasses,  graduated  scale,  etc.,  omitting  the  meter  as 
shown.  Two  kinds  of  cylinder  oil  may  be  used.  Care  will  be 
taken  that  the  pipe  lines  be  located  in  warm  places  so  that  the  flow 
of  oil  will  not  be  sluggish  in  cold  weather.  It  will  be  noticed  that 
a  connection  is  led  off  from  the  bottom  of  the  tank  so  that  in  case 
the  pressure  for  any  reason  is  lacking  in  the  supply  lines^  oil  for 
hand  filling  may  then  be  withdrawn  and  the  entire  piping  arrange- 
ment as  shown  in  Fig.  58  be  shut  down  for  repairs.  This  feature 
is  the  most  valuable  one  of  this  system;  this  supply  system  is 
merely  a  convenience  and  labor-saving  device  and  not  necessary  for 
operation.  The  piping  system  just  described  can  be  used  in  con- 
nection with  the  regular  sight-feed  lubricators;  the  pipe  line  would 
furnish  oil  to  the  lubricators  by  shutting  off  the  steam  pressure, 
opening  the  bottom  drain,  filling  the  lubricator,  closing  the  oil 
valve  and  opening  the  lubricator  into  the  steam  line  again.  Such 
a  method  of  operation  would  be  more  reliable  than  that  shown 
in  Fig.  55  because  each  lubricator  would  be  complete  in  itself 
and  in  time  of  disorder  to  the  general  system  could  be  hand 
filled. 

Journal  Lubrication.  The  subject  of  handling  engine  or  journal 
oil  will  next  be  considered.  This  is  a  subject  that  affords  much 
opportunity  for  study.  The  great  variety  of  oil  handling  systems 
now  in  use  seems  to  illustrate  a  lack  of  knowledge  of  this  subject 
because  of  the  widely  different  types  of  apparatus  employed  for 
the  same  service. 

A  few  general  characteristics  of  oils  should  be  borne  in  mind 
when  considering  this  subject: 

1.  Engine  oil  never  "wears  out."     Its  value  as  a  lubricant  im- 
proves by  wear,  if  it  is  kept  free  from  all  foreign  materials. 

2.  Oil  will  incorporate  with  water  under  certain  operating  con- 
ditions and  the  water  so  incorporated  will  not  precipitate. 

3.  Oil  containing  animal  fats  and  water  will  become  frothed  by 
agitation.     This  quality  can  be  determined  by  shaking    a    half 
filled  bottle. 

4.  The  better  the  lubricative  qualities  of  oil,  the  more  readily 
will  water  incorporate  with  it. 

5.  Precipitation  will  remove  impurities  which  cannot  be  filtered 
out  of  used  oil. 


AIR   AND    OILING   SYSTEMS.  89 

6.  Filtration  to  be  effective  must  be  carried  on  slowly,  and  the 
filter  bed  frequently  renewed. 

7.  The  process  of  evaporation  will  alone  liberate  water  incor- 
porated with  oil. 

8.  Paraffine  serves  no  useful  purpose  as  a  lubricant,  but  causes 
gumming  and  retards  perfect  distribution  in  the  journal. 

9.  Cylinder  oil  added  to  a  journal  lubricating  system  makes  the 
oil  less  fluid  and  if  engine  oil  is  properly  compounded  any  added 
fats  are  detrimental. 

An  oiling  system  should  be  purely  a  commercial  proposition;  a 
means  of  saving  in  the  cost  of  operation.  It  should  reduce  the 
quantity  of  oil  used  and  the  amount  of  labor  required  for  handling. 
The  plan  of  piping  oil  to  such  parts  of  an  engine  as  journals,  pins, 
etc.,  whose  rapid  motion  tends  to  throw  off  the  oil,  is  a  useless 
one  if  no  provision  is  made  for  catching  the  drips.  An  oiling  sys- 
tem has  a  tendency  for  accustoming  its  operators  to  the  use  of  large 
amounts  of  oil  and  it  thus  becomes  practically  impossible  to  induce 
an  operator  to  regulate  the  flow  of  oil  so  that  it  will  be  just  suffi- 
cient for  lubrication  and  not  allow  any  waste  in  drips. 

Early  in  the  design  and  plans  for  a  station,  the  decision  should 
be  made  as  to  whether  or  not  an  oiling  system  will  be  used,  so  that 
when  the  machinery  is  ordered  there  can  be  incorporated  in  the 
design  such  details  as  will  help  to  make  an  efficient  and  effective 
oiling  system.  Main  journals,  crank  pins,  cross  heads  and  similar 
parts  should  be  provided  with  oil  guards,  pockets,  drains,  etc.,  and 
it  should  be  specified  that  all  bearings  be  guarded  so  that  when  a 
continuous  stream  of  oil  is  fed,  all  the  surplus  oil  will  be  caught  and 
directed  into  drain  openings  and  thus  returned  to  the  system. 
Bearings  that  cannot  safely  be  flooded  with  oil  do  not  belong  on  an 
oiling  system. 

Under  quite  ordinary  conditions  the  engine  of  a  i,5oo-kw.  unit 
would  have  oil  fed  to  it  at  the  rate  of  a  barrel  an  hour,  which 
would  be  called  simply,  "liberal  lubrication."  When  men  get 
accustomed  to  seeing  oil  fed  in  this  manner  it  is  useless  to  try  to 
induce  them  to  feed  through  an  oiling  system  at  the  rate  of  a  drop 
a  minute. 

For  such  bearings  as  have  no  oil  guards,  the  only  practical 
method  is  to  insist  that  these  bearings  be  oiled  by  hand  and  thus 
the  attendants  will  use  as  little  oil  as  possible  and  save  themselves 
extra  labor  in  filling.  Many  of  the  unguarded  journals,  such  as 


9O  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

small  wrist  pins,  valve  gears,  etc.,  can  be  well  and  economically 
lubricated  by  using  grease  in  compression  cups.  Sponge  grease  is 
quite  successfully  used  on  valve  gears  of  extremely  high  tempera- 
ture. Those  bearings  not  provided  with  oil  guards  or  grease  cups 
should  have  an  ample  number  of  oil  holes  suitable  for  lubrication 
from  a  hand  oiler. 

A  return  oiling  system  should  serve  the  following  engine  bear- 
ings: Main  bearings,  crank  and  crosshead  pins,  cross  head  guides, 
eccentrics  and  stationary  rocker  pins  of  Corliss  engines  which  have 
drip  pans  under  them.  It  should  be  specified  that  the  vacuum 
pump  be  provided  with  oil  guards  and  drains  for  these  same  bear- 
ings. Much  trouble  is  occasioned  by  the  lack  of  forethought  when 
ordering  machinery,  because  it  is  useless  to  make  provision  for 
flooding  a  journal  with  oil  if  there  is  no  provision  made  for  caring 
for  the  waste  oil  and  thereby  allowing  it  to  discharge  onto  the  floor. 
The  only  method  left  in  a  case  of  this  kind  is  to  use  extremely  high 
grade  oil,  fill  the  cups  by  hand  and  endeavor  to  have  no  drips.  In 
this  case  the  practical  method  of  learning  when  to  check  the  oil 
supply  is  to  notice  whether  the  oil  has  run  down  onto  the  floor  on 
account  of  too  great  a  supply  or  whether  too  little  oil  has  caused 
a  hot  bearing.  Such  a  method  of  feeding  oil  is  extremely  expen- 
sive, not  only  on  account  of  the  oil  wasted,  but  because  of  the 
injuries  occasionally  caused  by  hot  bearings  and  the  extra  labor 
needed  in  constantly  watching  the  oil  feeds.  As  stated  before,  the 
machinery  must  be  fitted  for  an  oiling  system  in  order  that  the 
use  of  such  a  device  may  be  justified.  The  running  of  a  lot  of  pipes 
to  an  equal  number  of  oil  cups  signifies  nothing  more  than  that  it 
takes  the  place  of  a  man  carrying  the  oil.  The  economy  of  an 
oiling  system  does  not  make  itself  appreciable  when  the  journals 
have  not  been  provided  with  a  means  for  carrying  away  the  drips 
and  reusing  them. 

It  may  seem  all  right  to  say,  "We  will  take  up  the  matter  of 
the  oiling  system  when  we  come  to  it."  The  fact  of  the  matter 
is  that  an  engineer  has  "come  to  it"  with  every  system  to  be 
installed  the  moment  he  starts  writing  the  specifications  for  appa- 
ratus. He  should  by  all  means  lay  out  all  the  diagrams  for  the 
entire  plant  before  ordering  anything. 

Various  systems  are  in  use  for  delivering  oil  to  engine  bearings 
and  returning  drips  to  drip  tanks.  One  system  is  the  same  as  that 
shown  in  Fig.  57  for  cylinder  oil.  The  tanks,  pumps,  pump  gover- 


AIR   AND   OILING   SYSTEMS.  $1 

nors  and  distribution  main,  also  the  method  of  taking  steam  from 
two  sections  of  the  main  header,  are  the  same;  the  only  difference 
is  that  the  pressure  used  is  not  as  high  as  that  in  a  high  pressure 
cylinder  oil  piping  system.  The  same  objections  arise  in  handling 
engine  oil  as  have  been  stated  regarding  the  use  of  cylinder  oil; 
that  is,  the  pressure  varies  to  such  an  extent  that  it  changes  the 
quantity  of  oil  fed  to  the  journals. 

The  system  shown  in  Fig.  56  is  also  applied  in  using  engine  oil, 
the  ability  to  maintain  a  constant  pressure  is  gaged  by  the  sensitive- 
ness of  the  air  compressor  controller.  Such  a  system  necessarily 
gives  a  perceptible  variation  in  the  oil  discharge  whenever  the  air 
lines  are  used  for  other  service  besides  supplying  the  oil  tank.  It 
is  quite  unnecessary  to  measure  the  quantity  of  engine  oil  used  in 
a  return  system,  because  it  is  difficult  to  effect  any  perceptible  saving 
when  drips  are  returned.  An  operator  may  run  ten  barrels  through 
the  system  during  his  shift  and  the  shrinkage  on  this  amount  dur- 
ing its  circulation  may  not  exceed  one  gallon.  A  very  compli- 
cated system  would  be  required  if  it  were  necessary  to  have  such  a 
large  storage  capacity  and  care  for  such  volumes  of  oil  and  then 
be  called  upon  to  measure  the  loss  of  but  one  gallon.  In  practice 
this  has  not  been  considered  at  all  essential.  The  chief  require- 
ment for  an  engine  oiling  system  as  before  mentioned  is  that  it  may 
be  thrown  out  of  service  on  a  moment's  notice  and  some  hand 
system  substituted  without  necessitating  the  stopping  of  the  engine 
or  in  any  way  endangering  the  journals.  The  system  should  be 
merely  a  convenience,  readily  dispensed  with  when  necessary. 

There  are  many  styles  of  oil  cups  or  feeders  used  to  control 
the  amount  of  oil  fed  to  an  engine.  The  style  most  commonly 
used,  due  possibly  to  the  fact  that  it  was  originally  used  in  hand 
oiling  and  was  furnished  with  the  engine,  is  the  regular  pattern 
sight-feed  glass  oil  cup  with  the  hole  drilled  in  the  top  for  a  pipe 
nipple  to  attach  the  oil  piping  to  the  cup.  A  valve  is  placed  in  the 
line  to  the  cup  for  regulating  the  flow  to  the  cup  the  same  as  the 
regulated  flow  from  the  cup  to  the  bearing.  The  necessity  of 
watching  the  cups  in  this  style  of  feed  is  its  most  objectionable 
feature  because  it  requires  very  frequent  regulation  of  the  valve, 
and  if  not  closely  watched  the  oil  will  spill  over  the  top  or  the 
cup  will  run  empty.  The  latter  condition  would  be  shown  very 
conspicuously.  This  style  of  cup  requires  constant  watching  of  the 
feed  and  much  manipulation  of  the  valves. 


92  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

A  second  style  is  that  of  the  closed  glass-body  pressure-cup  with 
one  hand  regulating  valve.  This  cup  requires  less  attention  than 
the  first  style  and  it  has  only  one-half  as  many  valves  to  shut  off 
when  closing  down  the  system.  The  glass,  however,  is  under 
pressure  and  a  slight  crack  in  it  will  cause  a  bad  leak,  and  for  the 
same  reason  the  joints  at  the  ends  of  the  glass  must  be  securely 
made.  These  cups  can  be  filled  by  hand  by  closing  the  valve  in 
the  pipe  supply  and  removing  the  plug. 

The  third  style  is  merely  a  regulating  valve,  there  being  two 
forms,  hand  closing  and  self  closing.  The  hand  closing  valve  can 
be  set  for  the  desired  feed,  so  that  when  shutting  down  the  machine 
and  turning  over  the  cam  or  other  device  this  closes  off  the  oil 
flow  but  retains  the  set  for  feeding.  This  style  of  valve  is  made 
by  one  manufacturer  in  conjunction  with  a  regular  glass  sight- 
feed  cup,  making  a  separate  device  of  each  up  to  the  drop  sight 
glass.  Automatic  or  self  closing  feeder  valves  are  either  of  the' 
diaphragm  or  the  piston  form.  An  objection  to  the  diaphragm 
form  is  that  it  requires  a  very  high  pressure  on  the  oil  lines  to 
operate,  usually  about  60  to  80  Ib.  when  the  copper  diaphragm  is 
old  and  hardened.  The  piston  form  with  a  leak  port  to  the  journal 
works  on  as  low  as  a  i5-ft.  head,  making  this  type  very  satisfactory 
for  use  with  gravity  systems. 

Self  closing  valves  are  arranged  to  discharge  oil  to  the  bearings 
by  opening  the  one  oil  main  valve,  thus  allowing  the  pressure  to 
open  the  automatic  valves  to  the  set  position.  Diaphragm  auto- 
matic valves  are  not  used  except  with  high  pressure  oiling  systems. 
This  is  due  to  the  pressure  required  for  opening  them,  and  the 
success  of  the  operation  of  the  machinery  is  contingent  upon  the 
successful  operation  of  the  oiling  system.  In  other  words,  an  oiling 
system  of  this  type  must  always  be  in  effective  operation  for  con- 
tinued running  and  therefore  is  not  merely  a  convenience. 

The  requirements  are  very  satisfactorily  met  by  the  piston  type 
automatic  valve  with  hand  arrangement  for  feeding  and  regulating, 
when  oil  is  fed  by  hand.  This  style  allows  the  use  of  gravity  oil- 
ing systems,  is  self  closing,  free  from  glass  parts  and  can  be  used 
with  a  small  reservoir  at  each  engine  as  shown  in  Fig.  59  and  allow 
the  shutting  off  of  the  main  parts  of  the  oiling  system,  or  it  can  be 
used  independent  of  all  piping  as  a  separate  hand-fed  cup.  An 
engine  oiling  system  of  this  type  would  have  as  one  of  its  details  an 
emergency  tank  placed  just  above  the  highest  cup  and  arranged 


AIR   AND    OILING   SYSTEMS.  93 

so  that  it  could  be  filled  by  hand  during  those  times  when  the 
oil  main  is  out  of  service.  Should  the  lines  on  the  engine  be 
damaged  during  operation  the  entire  engine  piping  system  could  be 
shut  off  and  the  cups  hand  filled  until  the  damaged  section  was 
capped  up.  Then  the  piping  system  would  be  opened  and  again 
be  allowed  to  feed  into  the  cups.  If  one  or  two  of  the  cups  were  on 
the  damaged  portion  of  the  pipe  they  could  be  filled  by  hand  until 
such  time  as  the  engine  could  be  shut  down  and  the  pipe  work 
repaired.  In  regular  service  when  the  engine  is  to  be  started  the 
stop  valve  A  is  opened,  then 
all  cups  open  from  the  oil 
pressure  and  start  flowing. 
On  shutting  down  the  engine 
the  valve  A  is  closed  and  the 
lack  of  pressure  to  the  engine 

oil  Supply  allows   all   the   Cups    FIG.  59.  System;  Independent  Hand  Supply 

to  close  automatically.  This  ufeSyS*  ^  Conjunction  with Pipe 
is  quite  a  valuable  feature 

on  a  large  compound  engine  that  has  between  twenty-four  and 
thirty  cups,  and  especially  is  it  advantageous  over  a  system  of  cups 
whose  set  must  be  disturbed  to  close  the  cups. 

The  supply  to  the  feed  main  can  be  of  the  low  pressure  or  gravity 
system  for  any  of  the  different  styles  of  feeders  except  the  dia- 
phragm pattern  self-closing  cup.  This  latter  type  must  be  used 
with  a  fairly  high  pressure  system  if  satisfactory  operation  is  to  be 
insured,  and  so  gravity  pressure  is  quite  out  of  the  question,  because 
the  head  required  for  8o-lb.  pressure  in  a  gravity  system  would 
be  185  ft.  above  the  cups  or  somewhere  near  the  top  of  the 
stack. 

There  are  various  methods  of  supplying  the  oil  main  but  thes-e 
requirements  must  be  provided  for  if  it  is  wished  to  have  a  prac- 
tical and  satisfactory  system: 

1.  Any  piece  of  machinery  used  to  supply  the  oiling  system  must 
be  so  designed  that  it  will  permit  of  its  being  shut  down  for  an 
hour  or  two  without  stopping  the  supply  of  oil  to  the  engines. 

2.  All  tanks,  filters,  and  similar  apparatus  should  be  of  the  open 
pattern,  which  will  permit  complete  inspection  at  any  time. 

3.  Means  must  be  provided  for  discharging  any  water  returning 
with  the  oil  drips. 

4.  All  tanks,  filters  and  similar  apparatus  must  be  so  designed 


94 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


that  they  will  permit  of  thorough  cleaning  while  the  system  is  in 
operation. 

5.  Drip  lines  should  be  so  designed  that  any  branch  or  section 
can  be  cleaned  out  without  taking  the  pipe  work  apart. 

6.  The  system  should  be  so  arranged  that  it  will  operate  con- 
tinuously and  not  require  constant  watching  to  see  that  one  tank 
will  not  overflow,  another  run  empty,  etc. 

Some  of  the  systems  for  supplying  oil  do  not  satisfy  these  require- 
ments; for  instance,  engine  oil  supplied  to  the  main  by  a  pump 
and  governor  as  in  Fig.  57  requires  the  continued  operation  of  the 


FIG.  60.   System;  Oil  Drip  Return,  Filters,  and  Air  Pressure  Oil  Tanks. 

pump.  The  system  shown  in  Fig.  56  requires  the  air  compressor 
to  be  in  operation  continuously  unless  the  storage  air  tank  is  of 
sufficient  capacity  to  allow  air  to  expand,  say,  from  20  Ib.  down 
to  10  Ib.  in  discharging  oil  for  2  hr.,  which  discharge  may  be 
4  bbl.  A  tank  of  about  16  bbl.  capacity  or  100  cu.  ft.  would  be 
required  to  run  such  a  system  for  2  hr.,  but  ordinarily  the  air 
tanks  would  not  have  over  2  or  3  bbl.  capacity,  which  would 
be  sufficient  for  only  20  min.  run.  Another  objection  to  the  air 
system  is  the  inability  to  properly  clean  the  tanks,  since  they  are 
closed  in  from  view  so  that  their  condition  cannot  be  noted. 

Probably  as  satisfactory  an  air  system  as  can  be  laid  out  is 
shown  in  Fig.  60.  It  will  be  noted  that  the  tanks  and  air  com- 
pressors are  in  duplicate.  The  filters  are  also  in  duplicate  and 


AIR   AND   OILING   SYSTEMS.  95 

arranged  so  that  both  can  be  worked  in  parallel,  not  in  series, 
because  the  work  done  in  a  filter  depends  upon  the  velocity  of  the 
flow  through  the  filtrate.  The  small  open  tank  A  is  a  receiver, 
designed  to  take  the  discharge  from  the  filters  during  the  time  of 
changing  over  from  tank  B  to  tank  C.  When  tank  B  is  taking 
drips  from  the  filter,  tank  C  is  under  pressure.  When  the  oil 
becomes  low  in  the  tank  C,  the  drip  from  tank  A  is  closed  and  air 
pressure  is  put  on  tank  B ;  when  tank  B  is  under  pressure  the  valve 
to  the  oil  line  is  opened  and  tank  B  put  onto  the  system.  Then 
the  oil  valve  at  the  bottom  of  tank  C  is  closed,  air  vent  is  opened 
and  the  valve  between  tanks  A  and  C  is  opened,  thus  allowing  the 
filtered  oil  to  replenish  the  supply  in  tank  C.  If  these  tanks  have 
a  capacity  of  8  or  10  bbl.,  this  arrangement  of  valves  need  not  be 
disturbed  for  4  or  5  hrs.  The  tanks  B  and  C  accumulate  much 
impurity.  Unless  tank  A  has  sufficient  capacity  to  store  the 
drips  while  tanks  B  or  C  are  being  cleaned,  it  may  be  found 
necessary  to  do  this  after  shutting  down  the  machinery  at  night. 
The  device  D  must  be  a  dividing  arrangement  which  will  allow 
one  half  the  drips  to  flow  each  way,  and  this  is  rather  a  difficult 
detail  to  provide  if  it  is  wished  that  the  division  be  even  fairly 
accurate.  Although  not  shown  in  the  figure,  all  tanks  would  require 
sewer  connections  as  outlets  for  water,  refuse,  etc. 

This  system,,  Fig.  60,  fails  to  provide  the  necessary  previously 
stated  requirements,  2,  4  and  6,  and  unless  the  air  tanks  are  large 
it  will  fail  to  provide  for  requirement  i. 

Instead  of  using  air  as  a  pressure  supply  for  the  oil,  the  same 
system  as  that  shown  in  Fig.  60  can  have  its  pressure  supply  by 
water.  In  this  case  the  oil  would  be  taken  from  the  top  of  the 
tank  instead  of  the  bottom  and  the  water  would  be  admitted  at 
the  bottom.  The  use  of  water  in  oiling  systems  should  be  elim- 
inated as  much  as  possible,  not  only  in  tanks  B  and  C,  but  in  the 
filters,  because  enough  trouble  is  caused  by  water  incorporating 
with  the  oil,  even  though  every  precaution  is  taken  to  avoid  it.  In 
one  particular  case  the  system  shown  in  Fig.  60  was  originally 
equipped  for  water  pressure  and  was  operated  thus  until  the  con- 
dition of  the  oil  required  the  change  to  air  pressure;  about  30  per 
cent  of  that  which  was  supposed  to  be  oil  was  water  permanently 
carried  in  suspension. 

This  difficulty  does  not  appear  in  cylinder  oil  feeding  systems 
which  use  a  water  condensation  column  to  carry  oil  into  a  steam 


96  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

pipe,  because  cylinder  oil  is  much  heavier,  and  even  though  it 
would  take  up  water  the  fact  would  never  demonstrate  itself,  since 
the  oil  does  not  return  to  afford  the  chance  to  again  take  up  more 
water  and  thus  by  repeated  contact  combine  into  a  soapy  mass  of 
froth  and  foam  that  will  neither  flow  in  drain  pipes  nor  pass  by 
the  needle  valves  of  oil  cups. 


CHAPTER  VIII. 
OIL  AND  WATER  PURIFYING  SYSTEMS. 

Oil  Purifying  Systems.  The  filters  shown  in  Fig.  60  are  in  the 
path  of  the  return  drips  to  tanks  B  and  C.  If  the  beds  in  these 
filters  are  close  laid  and  suitable  for  effective  filtration,  then  in  case 
of  flooding  journals,  the  filter  will  be  flooded  and  overflow  onto  the 
floor.  Anyone  contemplating  the  use  of  filters  in  a  return  system 
must  provide  for  a  flow  through  them  somewhat  greater  than  the 
maximum  flow  fed  to  the  engines.  It  is  safe  to  estimate  that  this 
flow  will  equal  the  greatest  capacity  of  the  pipe  lines  which  supply 
the  cups.  In  designing  station  work  it  is  useless  to  design  for  only 
that  which  is  essential.  If  one  part  of  the  oiling  system  is  designed 
to  deliver  4  bbl.  of  oil  an  hour  to  the  bearings,  then  the  return 
part  of  the  system  should  have  a  like  capacity.  In  station  opera- 
tion it  is  not  an  uncommon  thing  to  see  an  operator  drag  a  hole 
through  the  filtering  material,  "so  the  oil  can  get  through,"  as  he 
will  say.  Usually  this  is  the  only  practical  thing  to  do. 

In  oil  cleansing  apparatus  using  filtering  material  a  satisfactory 
design  is  to  enclose  this  material  in  a  receptacle  similar  to  a 
galvanized  iron  tub.  This  tank  or  tub  should  have  a  perforated 
bottom  and  a  perforated  plate  laid  on  top  to  retain  the  filtering 
material.  In  case  the  filtering  material  is  6  in.  deep  and  the  sides 
of  the  tub  are  18  in.  high  if  12  in.  of  oil  pressure  on  top  of  the 
filtering  material  is  not  enough  to  force  the  oil  through,  it  can 
spill  over  the  edges  of  the  tub  into  a  tank  in  which  the  tub  should 
be  set.  This  may  seem  to  be  a  crude  method,  but  it  is  far  more 
effective  than  to  attempt  to  force  oil  under  a  high  head  through 
a  filter  bed  that  yet  contains  those  impurities  collected  from  the 
oil  while  it  was  flowing  more  slowly.  Such  a  system  collects 
impurities  at  one  time  and  then  when  an  overload  is  thrown  upon 
it  and  a  larger  quantity  of  oil  demanded,  this  oil  under  a  higher 
pressure  washes  the  previously  strained  impurities  through  the 
filtering  material  and  back  into  the  oil  mains.  Such  is  not  the 
case  with  the  "tub"  plan.  The  tub  filter  will  remove  whatever 

97 


98  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

impurities  it  can  and  the  others  will  flow  over  the  sides  with  the 
oil  and  be  picked  out  at  some  other  time. 

The  doubtful  value  of  an  oil  filtering  system  can  be  demon- 
strated by  a  simple  test.  Take  two  sample  bottles  of  oil,  one 
drawn  immediately  after  it  has  passed  through  the  filter,  and 
the  other  taken  before  being  filtered,  the  latter  first  having  been 
passed  through  a  fine  "milk  strainer"  wire  sieve  to  remove  foreign 
bodies,  such  as  lint,  scale,  etc.,  and  let  these  bottles  stand  undis- 
turbed for  a  month's  time.  Examine  them  closely  and  note  the 
marked  amount  of  clarifying  that  has  taken  place  as  a  result  of  pre- 
cipitation. The  observer  need  not  be  surprised  if  he  cannot  tell 
which  of  the  two  samples  of  oil  is  the  clearer.  He  should  note 
carefully  the  results  of  precipitation,  observing  the  large  amount  of 
separation  that  has  taken  place  while  he  has  been  trying  to  get 
equal  results  from  the  filter.  If  a  bottle  of  oil  can,  in  this  manner, 
be  so  thoroughly  purified,  why  not  subject  all  the  lubricating  oil 
to  this  same  treatment  ? 

To  accomplish  this  successfully  it  will  be  necessary  to  take  part 
of  the  oil  out  of  circulation  and  allow  it  to  remain  quiet  while 
precipitating.  Means  must  be  provided  for  drawing  off  the  clear 
oil  for  use  in  the  system  and  for  leading  into  an  empty  barrel  the 
heavy,  fatty  oil  lying  between  the  clear  oil  and  the  water.  The 
piping  should  be  arranged  so  that  the  water  can  be  run  from  the 
precipitation  tank  to  the  sewer  and  the  tank  thoroughly  cleaned. 
After  cleaning,  the  tank  can  be  filled  with  clear  oil  and  the  valves 
closed.  Then  the  "batch"  of  oil  that  has  in  the  meantime  been 
serving  the  machinery  can  be  subjected  to  the  same  process  of 
precipitation  with  like  results.  The  heavy,  fatty  oil  which  forms  in 
a  layer  in  the  precipitating  tank  is  wholly  unfit  for  piped  oiling 
systems,  but  can  be  made  use  of  elsewhere.  Ordinarily  much 
of  this  heavy,  fatty  oil  is  lost  in  cleaning  out  the  closed  tank. 

An  oil  supply  system  using  precipitating  tanks  is  shown  in  Fig.  61. 
The  two  precipitating  tanks  are  alternately  used,  one  as  a  gravity 
tank,  and  the  other  as  a  precipitating  tank.  From  the  pans 
under  the  engines  the  drips  are  separately  carried  to  drip  pots. 
The  lower  part  of  this  type  of  drip  pot  is  held  against  the  upper 
portion  by  a  stud  bolt  passing  through  the  center  of  the  top.  The 
joints  between  the  two  sections  should  be  ground  and  no  gaskets 
used.  The  purpose  of  these  drip  pots  is  to  catch  such  heavy  pre- 
cipitation as  would  lodge  and  choke  the  pipes.  These  pots  also 


OIL   AND    WATER   PURIFYING  SYSTEMS.  99 

take  the  place  of  T's  and  the  angles  are  turned  with  bends  in  place 
of  L's.  With  this  construction  there  are  no  corners  or  edges 
around  which  the  drips  must  pass  on  their  way  to  the  pot  and 
therefore  little  chance  for  clogging.  The  common  practice  of 
using  crosses  and  plugs  also  increases  the  liability  for  clogging. 
The  bent  pipe  avoids  these  obstructing  edges  and  corners  and 
furnishes  a  pipe  line  that  can  readily  be  cleaned  with  a  wire,  from 
the  inlet  all  the  way  through  to  the  drip  pot. 

There  are  two  discharges  into  the  receiving  tank;  A  is  the  regu- 
lar inlet  and  B  the  special  connection  to  be  used  when  the 
automatic  water  discharge  is  being  cleaned.  The  oil  drips  are 
conducted  to  a  point  low  down  in  the  water  separator  and  the 
cross  discharge  pipe  is  perforated,  with  the  openings  looking  down. 
The  water  overflow  is  located  2  in.  lower  than  the  oil  overflow. 
This  allows  20  in.  of  oil  over  the  water  in  the  separator.  The 
three  .upper  trays  shown  in  Fig.  61  are  provided  with  screen  wire 
bottoms.  The  lower  screen  tray  has  a  brass  wire  gauze  of  very 
fine  mesh.  These  trays  are  arranged  with  the  screens  graded  from 
coarse  at  the  top  to  the  very  fine  mesh  at  the  bottom,  so  that  each 
removes  its  particular  size  of  impurities.  If  the  top  one  becomes 
blocked  the  oil  will  then  run  over  the  edges  and  be  strained  in  a 
lower  one.  The  bottom  tray  has  but  one  opening.  This  is  located 
over  the  funnel  leading  to  the  oil  pump  suction.  The  tank  in 
which  these  trays  are  placed  should  be  provided  with  doors  in  its 
sides  to  facilitate  the  removal  of  the  trays  for  cleaning.  In  this 
way  the  trays  can  be  cleaned,  one  at  a  time,  during  regular  opera- 
tion. The  trays  should  be  set  back  sufficiently  far  from  the  clean- 
ing door  to  enable  an  operator  to  inspect  the  bottom  of  the  tank 
without  disturbing  the  position  of  the  trays.  To  aid  inspection  an 
electric  lamp  should  be  placed  inside  the  tank  as  shown  in  the 
figure.  The  edge  of  the  water  overflow  must  be  long,  say  18  in. 
or  more,  to  avoid  building  up  a  head  on  this  edge  when  discharging 
a  large  volume  of  water  as  would  be  the  case  when  the  drips  were 
being  flushed  with  hot  water.  To  care  for  a  flow  of  three  or  four 
barrels  of  oil  an  hour,  the  overflow  edge  between  the  separator 
and  the  tank  should  be  not  less,  than  12  in.  long. 

A  small  pump  is  shown  with  its  direct  connected  motor  of  the 
slow  speed  type  placed  above  the  pump  on  the  engine  room  floor. 
This  pump  should  be  of  the  slow  speed  rotary  type  so  that  it  will 
cause  the  least  amount  of  agitation  and  frothing  of  the  oil.  Tell- 


100 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


tales  are  shown  connected  to  the  tanks  overhead  and  in  view  from 
the  engine  room.  The  elevated  tanks  should  have  light,  loose 
covers  the  full  size  of  the  top  of  the  tank  with  suitable  openings  in 


FlG.  61.   System;  Gravity  Pressure  Oil  Supply,  with  Precipitation  Tanks. 

these  covers  for  the  removal  of  the  telltale  floats  during  that  time 
when  the  tanks  are  being  cleaned.  Around  the  tops  of  these  tanks, 
on  the  inside,  there  should  be  overflow  rings  with  the  overflow 
levels  about  4  in.  below  the  upper  edges  of  the  tank  shells.  In  the 
figure,  tank  C  is  shown  in  use  as  a  gravity  tank  and  D  as  a  precipi- 


OIL   AND    WATER   PURIFYING  SYSTEMS.  IOI 

tating  tank.  Tank  E  would  be  of  small  capacity,  not  over  half  a 
barrel ;  this  tank  is  used  in  connection  with  the  overflowing  of  the 
large  tanks  after  precipitation.  A  water  connection  is  run  to  the 
under  side  of  the  tanks.  By  this  means  the  contents  of  the  pre- 
cipitating tanks  can  be  raised  as  gradually  as  desired.  A  perfo- 
rated disk  is  placed  in  the  bottom  of  the  tank  to  dissipate  the  flow 
of  the  incoming  water  and  thus  avoid  disturbing  the  precipitate. 

Previous  to  the  withdrawing  of  the  clear  oil  from  a  precipitating 
tank,  the  drip  lines  and  receiving  , tank  should  have, been  well 
cleaned  out,  and  the  impure  oil  pumped Ikito  fonk  C.'-.^he  suction 
at  the  bottom  of  the  receiving  tank  should  be  operieqVto,  remove  all 
deposits.  For  illustrative  purposes  ian^/i'^will-be-ednsidered  as 
the  tank  which  has  been  furnishing  oil  to  the  bearings.  The  suc- 
tion to  the  receiving  tank  would  next  be  closed  and  oil  would  be 
drawn  from  the  lower  tight  bottom  tray  F  through  suction  G, 
closing  suctions  H  and  /.  The  discharge  of  the  pumps  will  keep 
the  dirty  oil  out  of  the  receiving  tank  and  allow  the  clean  oil  from 
the  precipitating  tank  D  to  run  into  the  receiving  tank.  Thus  the 
precipitating  tank  will  be  made  ready  to  circulate  clear  oil  again. 
After  tank  D  is  cleaned  the  suction  of  the  pump  is  then  changed 
from  G  to  H  and  the  discharge  is  reversed  from  tank  C  to  tank  D, 
and  as  soon  as  oil  is  over  the  discharge  opening,  the  oil  main  dis- 
charge of  tank  C  is  closed  and  D  is  opened.  By  this  cycle  of 
operations  the  system  has  been  cleaned  and  tank  C  is  now  out  of 
service,  full  of  oil  and  ready  to  remain  undisturbed  while  the 
impurities  precipitate.  Funnels  are  placed  under  the  tank  wash- 
outs to  enable  inspection  while  drawing  off  water  and  to  avoid 
losing  oil.  Steam  is  carried  up  to  the  gravity  tank  to  be  united 
with  water  for  cleaning  purposes.  The  size  of  tank  E  is  such  that 
it  will  hold  the  refuse  oil,  thus  giving  the  attendant  an  opportunity 
to  draw  off  this  oil  from  the  precipitating  tank  before  going  to  the 
basement  to  arrange  for  the  discharge  of  this  refuse  into  a  storage 
barrel. 

The  operation  of  this  system  is  continuous  and  if  the  pump  is 
run  all  the  time  there  will  be  no  occasion  for  watching  any  portion 
of  the  system.  Even  though  the  pump  be  shut  down,  the  telltale 
would  show  plainly  at  all  times  and  the  pump  motor  starting  box 
would  be  convenient  for  starting  or  stopping  the  motor  at  any 
time.  The  pump  should  be  located  below  the  oil  tank  so  that  its 
suction  will  always  be  filled  with  oil.  The  gravity  tank  can  be 


102  STEAM  POWER  PLANT  PIPING   SYSTEMS. 

filled  only  to  one  height.  At  this  level  the  oil  will  overflow  into 
tank  E.  When  the  latter  tank  is  filled  it  will  overflow  and  the 
excess  oil  be  returned  to  the  receiving  tank.  There  should  be  no 
valves  in  the  return  overflow. 

This  system  covers  the  requirements  very  thoroughly;  the  only 
additional  precaution  that  might  be  advisable  would  be  to  place  a 
small  steam  pump  or  another  duplicate  motor  driven  pump  in  this 
system.  The  additional  pump  would  serve  as  a  reserve  and  permit 
repairs  to. ,  the  regular  motor  driven  pump  while  the  oiling  system 
was  in  regular  opetatipfc.*;  il^ie  precipitating  tanks  would  be  of 
sufficient  size.  to. hold,  enough  oil  to  run  the  plant  possibly  three  or 
four  hours.*- ' ; .**: *%*  nr •:..,:  .*«\  •->.." 

In  Fig.  62  a  more  detailed  system  is  shown  for  the  arrangement 
of  lines  essential  to  continued  operation.  It  will  be  noted  that  two 
pumps  are  shown.  In  fact  it  is  not  possible  to  lay  out  a  systematic 
plan  for  continuous  operation  having  but  one  machine  for  any  par- 
ticular service.  One  of  these  pumps  could  be  steam  driven  and 
answer  all  demands  except  convenience  of  operation;  a  small 
steam  pump  is  generally  a  nuisance  as  the  cylinders  become  filled 
with  condensation,  the  packings  at  the  rods  are  constantly  leaking, 
and  due  to  the  fact  that  the  pumps  should  be  placed  below  the 
receiving  tank  this  ordinarily  locates  the  little  pump  in  the  dark, 
out  of  the  way  place  so  that  it  gets  little  inspection  and  thus  a 
close  watch  must  be  kept  of  the  telltale  to  be  sure  that  the  pump  is 
running  properly.  With  a  rotary  pump  in  the  basement  at  the 
tank  and  the  motor  on  the  engine  room  floor  it  is  very  evident 
what  the  pump  is  doing. 

Fig.  62  shows  the  drips  of  each  unit,  collected  and  run  separately 
to  a  funnel  on  the  receiving  tank.  This  is  the  most  reliable  method 
as  it  is  thus  quite  possible  to  clean  all  the  pipes  of  an  engine  while 
out  of  service  or  to  take  down  any  one  of  them  without  interfer- 
ing with  the  operation  of  the  other  drips.  The  loop  system  for 
drips  is  not  practical  since  the  drips  require  a  fall  to  aid  in  keep- 
ing the  pipes  clean.  An  oiling  system  is  a  class  of  service  that  is 
difficult  to  systematize  and  it  is  a  service  that  may  block  up  and 
give  trouble  at  almost  any  time.  The  lines  should  all  be  as  free 
from  valves  and  fittings  as  is  possible. 

Perhaps  a  better  detail  for  a  long  drip  main  could  be  made  by 
using  a  heavy  galvanized  iron  open  top  gutter  well  supported  and 
covered  with  sectional  lipped  covers.  This  gutter  could  be  cleaned 


OIL   AND    WATER   PURIFYING   SYSTEMS. 


103 


out  readily  while  the  plant  was  in  operation  and  by  having  separate 
connections  to  the  tanks  it  would  be  possible  quickly  to  throw  out 
the  tank  in  use  and  use  the  precipitating  tank,  possibly  drawing 
off  the  precipitated  water  before  doing  so.  There  is  no  serious 


&#&% 

FlG.  62.    Sample  System  ;  Shown  in  Fig.  61  and  Arranged  for  Continuous  Service. 

objection,  on  a  score  of  continued  operation,  to  the  using  of  but  one 
receiving  tank,  because  there  are  two  separate  compartments  in 
the  tank  with  separate  discharges  into  each  and  separate  suctions. 
With  the  system  shown  in  Fig.  62  it  is  possible  while  changing 
over  the  precipitating  tank  to  run  one  pump  on  the  bottom  tray, 
delivering  back  to  the  tank  that  has  been  in  use,  and  use  the  other 


104  STEAM   POWER   PLANT  PIPING  SYSTEMS. 

pump  to  raise  clear  oil  from  the  receiving  tank  back  into  the  clean 
gravity  tank,  both  pumps  being  run  during  this  period.  In  fact, 
there  are  too  many  advantages  in  the  use  of  two  oil  pumps  to 
endeavor  to  run  but.  one,  and  the  cost  is  too  slight  to  call  for  a  dif- 
ferent mode  of  operation.  If  it  is  found  necessary  at  any  time  to 
stop  the  pumps  for  a  considerable  period,  this  condition  may  find 
the  plant  running  short  handed  and  cause  much  disorganization 
among  the  operators.  This  is  one  of  the  chief  objects  to  keep  in 
mind  in  designing  systematic  station  layouts  —  that  is,  to  arrange 
the  details  so  that  it  will  be  possible  to  make  repairs  at  any  time 
and  not  interfere  with  the  regular  work  and  hours  of  labor  as 
assigned  to  the  station  help. 

Water  Treating  Plants.  There  is  another  class  of  station  piping 
systems  that  as  yet  has  not  been  considered;  this  is  the  system  of 
water  treating  plants.  There  are  virtually  three  styles  of  water 
treating  systems:  the  intermittent  open,  the  continuous  open,  and 
the  closed  continuous  system.  These  systems  will  not  be  dis- 
cussed in  detail  except  in  regard  to  their  piping.  The  open  systems 
are  very  large  and  are  customarily  placed  outside  of  the  power 
plant  proper.  The  pressure  system  is  ordinarily  placed  indoors 
and  conveniently  close  to  pumps,  heater,  etc.  The  open  systems 
are  operated  with  cold  or  warm  water;  the  higher  the  temperature 
of  the  water  the  more  quickly  will  the  chemical  reaction  take  place. 
The  advocates  of  cold  water  feeding  systems  argue  that  a  station 
may  not  at  all  times  be  able  to  furnish  warm  water,  therefore  the 
treatment  plan  should  meet  this  condition.  And  also,  if  a  plant 
has  capacity  for  part  of  the  time  with  cold  water,  it  can  always  be 
operated  at  this  or  a  greater  capacity;  hence  it  is  not  necessary  to 
heat  water  any  of  the  time. 

The  open  systems  require  elevating  water  to  the  upper  mixing 
tanks,  whence  it  flows  by  gravity  through  the  different  stages  until 
it  reaches  the  settling  tank.  In  all  the  water  treatment  systems 
the  boiler  feed  is  drawn  off  close  to  the  upper  surface,  since  the 
lower  water  is  in  the  path  of  the  descending  precipitates. 

The  builders  of  water  treating  plants  are  willing  to  use  steam 
from  a  steam  pump  that  handles  the  water  for  treating  service  be- 
cause steam  is  always  available  from  this  source  while  the  treating 
plant  is  in  operation.  In  case  condenser  discharge  water  is  cus- 
tomarily used  and  the  size  of  the  treating  plant  has  been  determined 
with  regard  to  the  temperature  of  this  water,  if  at  any  time  the 


OIL  AND    WATER  PURIFYING  SYSTEMS.  IO$ 

condensers  were  not  in  operation,  then  means  would  be  required  to 
raise  incoming  cold  water  to  the  same  or  higher  temperature.  The 
higher  temperature  required  is  on  account  of  the  fact  that  the 
engines  would  use  more  steam  and  thus  the  boilers  need  more 
treated  water  when  the  plant  was  running  non-condensing.  As 
the  demand  for  water  increases  beyond  the  capacity  of  the  tanks,  it 
is  necessary  to  increase  this  capacity  by  raising  the  temperature 
of  the  water,  and  for  every  given  temperature  of  water  there  is 
for  the  same  water  a  given  ultimate  capacity.  If  it  were  possible 


FIG.  63.    System;  Intermittent  Water  Treating  Plant. 

to  raise  the  temperature  of  the  water  to  that  of  steam  by  means 
of  an  open  live  steam  heater,  the  reaction  would  be  very  quick; 
in  fact,  the  high  temperature  alone,  without  chemical  reagents,  will 
precipitate  the  carbonates  and  sulphates  of  lime  and  magnesia  if 
allowed  sufficient  time  and  if  ample  surface  exposure  is  provided 
for  liberating  the  gas  that  holds  the  impurities  in  solution. 

An  open  intermittent  system  is  shown  in  Fig.  63.  This  arrange- 
ment requires  a  greater  amount  of  room  and  possibly  a  little  more 
attention  than  the  others,  but  it  possesses  points  of  merit  that  cannot 
otherwise  be  obtained.  A  predetermined  amount  of  chemical 
is  run  from  the  upper  tank  into  a  tank  full  of  water,  then  thoroughly 
agitated,  the  agitation  being  kept  up  during  the  entire  time  of 
chemical  reaction,  then  left  entirely  alone  and  undisturbed  while 
precipitation  takes  place. 

The  success  of  chemical  treatment  is  dependent  upon  two  condi- 
tions, absolute  proportioning  of  chemicals  and  water  throughout 


io6 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


the  entire  mass,  and  perfect  precipitation.  The  continuous  treat- 
ment requires  constant  measuring  of  chemicals  and  water  and  also 
a  constant  flow  of  water  during  the  time  precipitation  is  taking 
place.  It  will  be  noted  in  Fig.  63  that  the  exhaust  from  the  steam 
pump  is  run  to  a  closed  heater,  and  a  live  steam  connection  is  also 
provided,  which  may  be  used  in  case  of  an  increased  demand  for 
water,  but  it  should  be  remembered  that  too  small  a  plant  will 
increase  the  operating  expenses  both  for  chemicals  and  steam. 
If  ground  space  is  extremely  valuable  the  high  type  of  continuous 


FIG.  64.   Sample  System;  for  Water  Treating  Plant. 

system  will  be  a  more  suitable  arrangement.  Should  there  be 
no  space  available  outside  of  the  plant,  then  the  pressure  system 
will  show  to  an  advantage. 

The  piping  plan  for  the  intermittent  open  systems  should  be 
similar  to  that  shown  in  Fig.  64  in  case  it  is  to  be  applied  to  the 
power  station  plans  previously  considered,  and  shown  in  Fig.  19. 
If  an  intermittent  open  system  is  used,  it  would  be  advisable  to 
install  the  open  heater  as  shown  in  Fig.  64. 

As  in  the  case  of  continuous  systems,  if  the  water  were  running 
constantly  through  the  treating  plant  the  exhaust  heater  could  be 
differently  placed,  as  shown  in  Fig.  65;  then  all  the  atmospheric 
steam  would  be  used  to  heat  the  water  say  to  160  or  170  degrees 
before  passing  the  water  through  the  chemical  treatment.  By  this 
arrangement  the  low  pressure  pump  attached  to  the  feed  pump 
would  deliver  water  into  the  heater  and  the  heater  would  over- 
flow into  the  treating  plant.  The  boiler  feed  pump  would  then 
take  the  treated  water  by  suction.  This  arrangement  of  piping 
supplies  a  by-pass  around  the  heater  and  another  around  the 
treating  plant.  The  treating  plant  piping  should  be  as  simple 


OIL   AND    WATER   PURIFYING   SYSTEMS. 


10; 


as  possible;. this  plant  is  merely  to  improve  the  efficiency   of  the 
station,  and  in  case  of  repair  may  be  shut  down  at  any  time. 

The  mixer  shown  is  operated  generally  by  the  flow  or  weight  of 
the  incoming  water;  it  operates  on  the  plan  that  10  Ib.  of  water 
will  pump  or  otherwise  discharge  into  the  incoming  water  i  oz. 
of  liquid  chemical,  or  such  other  volume  as  the  device  is  set  for. 


FIG.  65.   System;  Continuous  Water  Treating  Plant. 

The  pressure  chemical  treating  plants  are  evidently  all  designed 
with  the  single  idea  of  "compactness,"  and  since  this  is  their  excuse 
for  existence,  it  may  also  be  called  their  advantage. 

Fig.  66  shows  a  closed  system.  The  open  heater,  A ,  is  arranged 
with  the  precipitating  chamber  a  part  of  and  beneath  it.  B  and  C 
are  the  niters.  D  is  the  pump  with  a  double  water  end,  one  cylin- 
der g  arranged  to  pump  water  up  into  the  heater,  the  other  cylinder 
h,  designed  to  pump  through  the  filters  to  the  boilers.  The  tank  E 
is  for  diluted  chemicals  which  are  pumped  by  the  chemical  pump  F. 
Instead  of  driving  the  cylinder  of  pump  F  by  an  ordinary  steam 
cylinder,  the  cylinder  is  arranged  with  no  valve,  but  having  a  hole 
under  each  end  and  a  pipe  run  from  each  hole  to  the  proper  end  of 
the  boiler  feed  pump  cylinders.  Thus  the  little  chemical  pump  is 
operated  by  and  in  unison  with  the  feed  pump,  feeding  one  cylinder 
of  chemical  compound  to  one  of  feed  water. 

The  regular  operation  of  the  filters  is  to  feed  through  the  top  of 
the  tanks  and  discharge  from  the  bottom  to  the  feed  main.  The 
filters  may  be  run  in  series  or  in  parallel.  When  cleaning  a  filter, 


io8 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


the  feed  main  connection  is  closed,  as  are  the  heater  or.small  pump 
connections ;  the  blow-offs  are  to  exhaust  across  the  top  of  the  filter 
bed,  underneath,  and  up  through  the  filter  bed.  Filters  are  used  for 
this  system  because  tanks  of  their  size  would  be  too  small  to  allow 
water  to  come  to  a  state  of  rest  and  permit  the  impurities  to  pre- 


FIG.  66.   System;  Pressure  Water  Treating  Plant. 

cipitate.  For  this  same  reason  filters  are  also  necessary  for  an  open, 
intermittent  or  continuous  system,  if  ample  time  for  precipitation  is 
not  to  be  had. 

There  are  some  interesting  details  in  connection  with  the  different 
systems  previously  shown.  These  will  be  considered  in  the  same 
order  as  the  diagrams.  There  are  various  minor  systems  that  will 
not  be  further  considered  except  in  connection  with  later  detail 
work.  It  would  be  useless  to  endeavor  to  plan  diagrams  that  could 
be  used  as  model  layouts  and  suitable  for  duplication  in  regular 
work.  No  two  engineers  have  even  similar  ideas  in  regard  to  a 
general  layout  of  station  requirements;  in  fact,  no  engineer  would 
duplicate  his  own  previous  work.  It  is  only  by  planning  and  exe- 
cuting that  which  is  not  right  that  we  learn  what  to  evade  on  other 
work,  and  each  evasion  of  previous  difficulties  only  brings  us  in 
contact  with  new  ones.  The  chief  object  in  showing  these  various 
systems  and  diagrams  has  been  to  illustrate  what  not  to  do  rather 
than  what  to  do.  There  is  a  great  laxity  in  the  methods  employed 
in  laying  out  station  work  in  general,  and  if  these  diagrams  suggest 
a  method  of  securing  a  more  perfect  system  this  publication  will 
have  accomplished  all  that  is  anticipated  for  it. 


CHAPTER  IX. 
PIPING  DETAILS. 

Classification.  Under  this  heading  will  be  shown  some  details 
of  construction,  including  the  assembly  of  the  various  parts  as  well 
as  special  details  pertaining  to  these  parts.  The  illustrations  of 
systems  previously  shown  were  merely  diagrams,  and  until  such 
diagrams  have  been  laid  out,  and  the  selection  of  the  system  to 
employ  has  been  finally  decided,  but  little  progress  can  be  made  in 
determining  details.  Detail  work  and  accurate  scale  drawings 
should  follow  the  diagram  layouts,  and,  although  the  diagrams 
may  be  considered  the  "key"  to  the  piping  plans,  they  should  not 
be  regarded  as  final  until  the  details  and  scale  drawings  are  com- 
pleted, as  it  may  be  found  that  some  minor  connection  can  be  made 
much  more  readily  by  slightly  modifying  the  system  rather  than 
running  a  special  long  or  otherwise  objectionable  connection. 

The  station  pipe  work  and  system  should  be  as  simple  as  it  is 
possible  to  have  them  without  sacrificing  their  reliability.  It  is  a 
very  common  mistake  in  pipe  work  design  to  complicate  the  system 
to  such  an  extent  —  in  the  attempt  to  provide  numerous  means  of 
supply  to  station  appliances  —  that  the  danger  of  interrupted 
operation  from  piping  difficulties  becomes  greater  than  that  from 
the  apparatus  which  is  being  safeguarded.  Power  station  design 
should  be  a  well-digested  compromise  of  all  the  various  station 
requirements.  If  the  designer  has  an  extensive  knowledge  of  but 
one  of  the  different  station  requirements,  such  for  instance  as 
electrical  work,  he  will  have  his  "diagram"  of  such  work  well 
developed  and  provided  for.  If  it  secures  better  results  to  have 
electrical  diagrams  well  determined  before  undertaking  the  details, 
why  should  not  piping  diagrams  be  given  similar  consideration  ? 

There  are  but  three  factors  included  in  the  systems  in  power 
station  construction,  viz.,  electrical,  piping,  and  coal  and  ash 
systems;  before  any  details  or  scale  drawings  are  attempted  a 
system  should  be  laid  out  in  diagram  combining  all  three  factors, 
as  each  is  affected  by  any  modification  of  the  other.  The  details 

109 


IIO  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

shown  in  the  following  pages  are  classified  according  to  the  system 
to  which  they  pertain;  for  example,  class  A  will  include  live  steam, 
class  B,  exhaust  steam,  etc.  The  number  affixed  to  the  class  letter 
represents  a  sub-division  of  that  class;  for  example,  Ai  represents 
"live  steam,  headers  or  mains";  A2  represents  "live  steam,  engine 
branches."  The  different  details  of  the  same  sub-classes  are 
numbered  serially,  as  AI-I  and  A 1-2,  etc.  It  would  be  well  for 
the  designer  to  construct,  according  to  this  system,  an  index  of 
details,  containing  all  the  different  classes  and  sub-classes. 

This  index  will  be  found  specially  useful  in  laying  out  diagrams, 
as  it  will  be  a  reminder  of  the  great  multitude  of  lines  and  con- 
nections that  enter  into  a  piping  system;  and  it  will  draw  to  the 
attention  of  the  pipe  work  designer  the  many  little  lines  and  con- 
nections that  are  easily  overlooked  in  preparing  drawings  and  speci- 
fications. These  oversights  often  make  pipe  work  "extras"  a  very 
large  item  in  station  building,  and  anyone  who  has  had  experience 
in  letting  contracts  knows  that  many  contractors  offer  bids  which 
permit  of  but  very  slight  profit,  depending  upon  "extras"  to  make 
the  job  a  desirable  contract.  The  index  will  aid  very  materially  in 
eliminating  these  extras,  which  not  only  result  in  a  very  expensive 
method  of  doing  the  work,  but  which  reflect  on  an  engineer's  ability 
to  properly  prepare  specifications. 

Another  advantage  in  using  such  an  index  is  that  it  avoids  the 
necessity  of  bearing  in  mind  every  line  and  connection  required, 
which  means  much  time  saved;  a  line  laid  out  with  a  connection 
overlooked  may  require  much  time  and  study  in  order  to  place  the 
missing  connection  at  some  point  where  no  provision  for  it  has  been 
made.  Space  should  be  left  after  each  class  in  the  index  to  enable 
the  designer  to  add  lines  or  connections  which  may  later  be  found 
necessary. 


CHAPTER  X. 
LIVE  STEAM  DETAILS. 

Class  Al  —  Live  Steam  Header  or  Main.  Detail  AI-I,  Fig.  67, 
shows  the  most  common  method  of  constructing  steam  mains  and 
headers,  using  wrought-iron  pipe  with  flanges  attached  to  it,  and 
cast-iron  fittings.  In  fact,  there  is  no  other  style  of  construction 
that  the  large  manufacturing  companies  will  guarantee.  The 
fittings  can  be  finished  so  as  to  have  parallel  and  right-angled  faces, 
and  the  flanges  on  the  pipe  can  be  faced  after  they  are  secured  to 
the  pipe,  insuring  a  perfectly  straight  pipe  line  when  assembled. 


FIG.  67.    (Ai-i.)  FIG.  68.     (Ai-2.) 

Detail  A 1-2,  Fig.  68,  shows  an  old  method  of  making  headers 
that  has  been  abandoned,  due  to  the  great  difficulty  of  keeping 
riveted  work  tight.  Riveted  work  should  be  completely  avoided 
for  any  lines  or  branches  that  are  subjected  to  strains  of  expansion 
and  contraction.  Another  objection  to  this  style  of  header  is  the 
inaccuracy  of  the  joint  faces.  The  nozzles  are  liable  to  have  flange 
faces  on  any  conceivable  plane  except  the  correct  one,  and  the 
flanges  at  the  ends  of  the  pipes,  which  are  set  by  hand,  are  sure  to 
be  out  of  true  in  some  direction,  the  amount  of  inaccuracy  depend- 
ing upon  the  care  taken  by  the  workmen  in  assembling  the  work. 
Hand  labor  is  a  very  uncertain  method  for  securing  accurate  work. 
If  the  conditions  are  such  as  to  demand  the  use  of  nozzles  riveted 
to  the  pipe  the  rivets  should  be  threaded,  stay  bolts  screwed  tight 
into  tapped  holes  and  riveted  over  each  end  to  avoid  leakage  past 
the  rivets.  The  flange  should  be  a  steel  casting,  so  that  it  can  be 
calked.  Instead  of  using  say  two  tees  in  the  header  for  two 
boilers,  and  another  tee  for  the  engine,  it  is  oftentimes  more  eco- 
nomical to  construct  one  casting  like  detail  A 1-3,  Fig.  69,  and  have 
fewer  joints  to  care  for. 

in 


112  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

It  may  occur  to  the  pipe  work  designer  that  he  would  be  depart- 
ing from  the  manufacturer's  standards  to  call  for  a  manifold  of 
this  style;  that  such  a  detail  would  require  special  pattern  work 
and  special  arrangement  of  tools  at  the  factory,  making  it  much 
more  expensive  to  build  than  two  standard  tees,  and  a  cross.  Large 
high  pressure  fittings  are  not  carried  in  stock  by  the  manufacturers, 
therefore  they  are  "specials"  in  the  machine  shop  even  though  they 
may  be  made  from  standard  patterns.  To  compare  the  cost  of  this 
manifold  with  a  manifold  made  from  three  separate  fittings  we  must 
consider  the  cost  of  patterns  against  that  of  four-faced  flanges, 


FIG.  69  (A  1-3). 


drilled  with  bolts  and  gaskets,  and  the  labor  for  making  the  joints. 
The  manifold  made  in  one  piece  will  invariably  cost  the  least,  and 
if  there  should  be  no  saving  in  cost  this  detail  is  decidedly  preferable 
from  an  operating  standpoint  on  account  of  its  easier  maintenance. 

In  order  to  lay  out  the  desired  system  it  may  be  found  necessary 
to  run  long  connections,  say  from  the  boiler,  in  order  to  place  the 
header  valves  according  to  the  diagram  previously  determined  upon. 
Such  a  case  is  shown  in  detail  A 1-4,  Fig.  70. 

The  system  should  never  be  sacrificed  for  any  notional  idea  of 
symmetry  of  connections.  To  preserve  the  desired  system  it  may 
be  found  necessary  to  increase  the  length  of  a  boiler  connection  say 
10  or  15  ft.,  a  feature  which  is  neither  expensive  to  construct  nor 
to  operate,  as  it  would  not  ordinarily  require  any  additional  fittings 
or  valves.  In  case  the  header  is  not  over  200  ft.  long  it  will  not 
require  any  other  provision  for  expansion  than  the  branches  to 
boilers  and  engines,  which  should  be  equal  to  a  full  length  of  pipe  in 
each  case.  By  anchoring  the  header  at  the  center,  the  expansion 
would  amount  to  about  two  inches  at  the  end  of  the  line,  and  this 


LIVE  STEAM  DETAILS. 

would  be  readily  taken  up  in  the  boiler  and  engine  branches.  The 
fitter  would  be  able  to  lighten  the  strains  by  drawing  the  end 
branches  about  an  inch  toward  the  center  of  the  header  when 
making  the  joint. 

If  the  connections  are  flanged  so  that  swings  may  be  used,  they 
will  relieve  themselves  on  the  flanged  faces  while  the  line  is  heating 
up,  and  greatly  reduce  the  strain  on  the  connections.  The  relief 
thus  afforded  can  be  demonstrated  by  opening  up  an  old  joint  and 
allowing  the  other  joint  to  throw  the  pipe  connections  into  la  posi- 
tion free  from  strain. 

In  cases  where  extremely  long  mains  are  used  it  becomes  neces- 
sary to  break  up  the  straight  line,  as  shown  in  the  detail  A 1-5, 
Fig.  71,  and  provide  anchors  for  the  steam  main  both  at  the  engine 
and '  the  boiler  branches.    In  cases  where 
it  is  desirable  to  keep  the  entire  length 
of  the  header  in  a  straight  line,  as'  would 
be  necessary  in  long,  straight  tunnel  work, 
it  becomes  necessary  to  take  care  of  the         \fffi,  flfcl* 
expansion   at   very  frequent   intervals  if 


elastic  details  are  used  to  care 
for  the  elongation  of  the  pipe. 
The  U-bend  for  dividing  head- 
ers is  the  most  common  method 
used  in  power  stations.  If  the 
bend  is  laid  flat  in  a  horizontal 
plane,  the  drips  will  flow  either 
FIG.  71  (A  1-5).  way  through  it;  however,  plac- 

ing   the   bend   in  a  horizontal 

plane  induces  severe  side  strains  on  header  supports,  and  these 
must  be  well  cared  for  to  prevent  the  header  from  climbing  up  on 
them  and  raising  itself  out  of  line.  Placing  a  U-bend  vertically 
throws  the  stresses  in  a  vertical  plane,  which  ordinarily  would  be 
fully  counteracted  by  the  weight  o/  the  header  and  branches;  the 
drips  must  be  cared  for  in  this  case  at  each  side  of  the  vertical 
U-bend.  Which  of  these  two  difficulties  can  be  the  more  readily 
cared  for  depends  upon  the  surrounding  conditions  of  each  in 
dividual  case. 


114  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

A  very  elastic  design  of  header  is  shown  in  detail  Ai-6,  Fig.  72, 
in  which  the  header  constitutes  merely  an  equalizer  from  one  mani- 
fold to  the  next.  The  sizes  shown  are  such  as  ordinarily  would  be 
used  for  a  2,ooo-kw.  unit.  The  manifolds  should  be  anchored  to 
their  supports,  and  throw  all  expansion  strains  onto  the  connecting 
lines.  Whatever  the  design  for  the  header  and  connections  may  be, 
it  should  be  so  arranged  that  the  elasticity  of  the  pipe  will  be  suf- 
ficient to  take  care  of  expansion  and  contraction.  This  is  the  only 
means* acknowledged  as  being  permanent  and  efficient.  There  are 
various  special  devices  for  caring  for  expansion,  but  their  use  is 


FIG.  72  (Ai-6). 

confined  to  emergency  cases  only,  or  cases  which  will  not  permit  the 
use  of  sufficient  length  of  pipe  to  secure  the  desired  flexibility. 

Supports  for  steam  mains  should  be  laid  out  to  allow  for  both 
expansion  and  the  side  movement  of  the  line,  as  illustrated  in  detail 
Ai-5>  Fig.  71.  The  points  in  the  pipe  line  that  would  be  the  center 
of  the  expansive  forces  should  be  anchored  to  avoid  vibration  of 
the  lines.  Expansion  and  vibration  are  two  conditions  that  must  be 
provided  for  and  neither  must  be  permitted  to  interfere  with  the 
other. 

The  fittings  ordinarily  used  for  large  steam  pipes  are  made  of 
cast  iron  and  are  extremely  heavy.  A  much  more  desirable  fitting 
could  be  made  of  soft  steel  'plate,  stamped  and  lap-welded,  as 
shown  in  detail  Ai-7,  Fig.  73. 

The  flanges  could  be  of  rolled  steel,  making  an  all-steel  fitting, 
light  and  somewhat  elastic.  If  the  manufacturer  had  his  factory 
equipped  with  proper  machinery  for  making  such  a  line  of  fittings 


LIVE   STEAM   DETAILS. 


he  could  without  doubt  produce  them  for  about  same  shop  cost  as 
cast-iron  fittings.  There  is  no  question  but  that  the  engineers  would 
be  universally  in  favor  of  using  the  steel  plate  fitting,  and  even  if 
their  cost  were  50  per  cent  more,  large  sized  fittings  would  in- 
variably be  specified  of  this  make.  A  demonstration  of  the  general 
desire  for  something  more  reliable  than  cast  iron 
is  .evidenced  by  the  very  extensive,  and  in  fact, 
almost  universal  use  of  rolled-steel  flanges  in  place 
of  cast-iron  ones,  which  were  formerly  used  for 
high  grade,  high  pressure  work.  Manufacturers 
are  using  what  they  term  "semi  steel"  for  high  ^  _  ?* 

pressure  valves  and  fittings,  and  for  no  other 
purpose  than  to  make  them  more  reliable.  Valves  cannot  be 
made  light  weight  and  of  extremely  strong  material,  as  it  is 
necessary  to  use  sufficient  metal  in  them  to  prevent  any  possible 
springing  or  distortion  that  would  prevent  the  valve  faces  from 
closing  tight.  Fittings,  however,  do  not  have  to  be  stiff  and  free 

from  distortion,  and  in  fact  the 
more  elastic  the  body  of  the 
fitting,  the  less  strain  there 
would  be  on  the  connecting 
lines. 

Class  A3  -  -  Live  Steam ; 
Engine  Branches.  The  con- 
nection shown  in  detail  A2-i, 
Fig.  74,  is  quite  frequently 
used,  as  it  allows  a  swing  on 
the  joint  faces  a  and  the  top 
of  the  throttle.  The  engine 
throttle  is  placed  at  the  lower 
end  of  the  branch,  allowing 

FIG.  74  (A2-i).  the  condensation  to  accumulate 

over  it  when  closed  —  a  con- 
dition that  would  be  very  objectionable  for  a  boiler  branch,  but  not 
with  the  engine  connection.  When  water  is  thrown  out  of  a  boiler 
branch  it  is  carried  to  the  engine  while  under  full  speed  and  in 
service.  An  engine  branch,  if  not  provided  with  a  drain,  will 
immediately  discharge  its  water  into  the  cylinder  and  the  engine 
while  slowly  starting  will  discharge  the  water  into  the  exhaust 
pipe  and  out  of  the  way.  The  drain  is  generally  the  warming  pipe, 


u6 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


and  before  the  engine  is  started  the  condensation  is  carried  off.  This 
style  of  connection  should  be  used  where  the  header  is  large,  and  it 
acts  as  a  separator  and  is  provided  with  drains.  The  dotted  lines 

show  a  connection  to  a  side- 
opening  throttle  which  has  a 
"triple-swing"  connection,  the 
same  as  shown  in  solid  lines. 
A  triple-swing  connection,  to 
be  such,  must  have  a  hori- 
zontal and  two  vertical  joint 
faces  at  one  end  of  the  con- 
nection, and  the  joint  face  at 
the  other  end  is  placed  so  that 
the  axial  line  passing  through 
its  center  will  not  coincide 
with  the  axial  center  line  of 
any  of  the  three  joint  faces  at 
FIG.  75  (A2-2).  the  other  end  of  the  con- 

nection.    To  secure  the  best 

results  possible  in  steam  pipe  connections,  it  is  necessary  to  use 
the  "triple-swing"  connection. 

Detail  A2-2,  Fig.  75,  shows  a  very  usual,  but  nevertheless 
improper  connection.  The  header  is  small  and  provided  with 
drains  and  the  receiver  also  is  small  and  provided  with  drain. 
Instead  of  separating  at  one  point  it  is  designed  to  separate  at  two. 
High  pressure  drips  are  troublesome  to  take  care  of,  and  the  fewer 
points  there  are  to  drain  the  simpler  will  be  the  system.  It  is  a 
very  common  practice  to  use  a  large  header  —  about  three  times 
the  area  of  the  engine  connection  —  and  depend  upon  the  pitch 
of  the  header  to  remove  the  water  carried  over  with  the  steam. 
This  makes  a  very  simple  arrangement  for  caring  for  drips,  as  one 
drip  line  will  care  for  the  entire  system.  The  objectionable  feature 
of  the  connection  shown  in  Fig.  75  is  that  it  is  necessary  to  drain 
at  two  different  points  instead  of  one. 

Detail  A 2-3,  Fig.  76,  shows  a  well  drained  system.  The  header 
is  of  just  sufficient  size  to  convey  the  steam  —  possibly  the  same 
size  as  the  engine  connection.  The  separator  is  say  twelve  times 
the  area  of  this  pipe,  which  greatly  retards  the  velocity,  and  provides 
a  large  volume  of  steam  close  to  the  engine.  This  receiver- 
separator  would  be  too  heavy  to  place  on  an  engine  throttle,  and, 


LIVE   STEAM   DETAILS. 


117 


as  shown,  would  be  a  support  for  the  header.  The  engine  branch 
can  be  readily  connected,  as  swings  are  provided  at  joints  a. 
To  take  a  branch  out  of  side  of  the  header  similar  to  that  taken  out 
of  the  receiver  would  be  bad  detail,  as  it  would  not  provide  the 
swing  that  is  always  necessary  for  good  pipe  work.  In  case  the 
steam  header  is  placed  below  the 
floor  the  same  details  would  obtain 
for  removing  condensation.  The 
receiver  located  below  the  header 
is  unquestionably  the  neatest  and 
safest  detail  of  this  class. 

Detail    A2~4,     Fig.    77,    shows 
the  horizontal    receiver-separator, 

which  may  also  be  placed  above  FIG.  76  (Aa-3). 

the  cylinder  with  the  throttle  on  top 

of  the  cylinder  in  the  usual  way,  as  shown  by  the  dotted  lines.  One 
of  the  great  advantages  in  the  use  of  separators  independent  of  the 
header  is  that  the  header  can  be  made  smaller,  which  permits  the 


FIG.  77  (A2-4). 

use  of  smaller  valves  and  involves  much  less  labor  in  making 
repairs,  the  vibration  is  reduced  and  the  general  operation  more 
satisfactory.  A  plant  that  would  require  a  2O-in.  separator-header 
would  in  case  of  using  receiver-separators  be  able  to  use  about  a 


Il8  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

14-in.  header.  However,  the  large  separator-header  should  not 
be  considered  anything  but  a  means  of  partial  separation,  as  the 
diameter  is  too  small  —  even  though  it  be  20  in.  —  and  would  cause 
the  velocity  of  the  steam  flow  to  be  about  four  times  that  through 
a  regular  separator. 

Class  A3  —  Live  Steam  Boiler  Branches.  The  connection  shown 
in  detail  A3~i,  Fig.  78,  is  one  of  the  most  approved  forms  of  boiler 
connection ;  it  has  the  triple  swing,  the  same  as  the  engine  connec- 
tion detail  A2-i.  It  is  quite  difficult,  and  in  fact  impractical,  to 
set  a  boiler  or  other  piped  device  by  the  face  of  its  pipe  connection, 
and  the  result  is  that  in  making  the  connection  between  a  header 
and  a  machine  there  are  slight  inaccuracies  in  every  direction ;  and 


FIG.  78  (A3-i). 


when  pipe  work  is  received  and  assembled  additional  inaccuracies 
become  apparent.  The  triple-swing  connection  provides  means 
of  taking  up  these  variations  by  rolling  the  different  parts  on  their 
faces.  In  case  the  elbow  were  turned  up  and  steam  entered  the 
header  at  the  bottom,  there  would  be  swings  provided  the  same  as 
shown.  The  connection  shown  in  detail  A3~i  has  two  valves,  a 
gate  valve  next  to  header  and  an  automatic  stop  valve  between  the 
gate  and  boiler,  both  valves  being  located  at  the  highest  portion  of 
the  branch,  insuring  a  dry  branch  at  all  times. 

The  connection  shown  in  detail  Aj-2,  Fig.  79,  has  a  double 
swing  —  on  the  three  flanges  a  and  the  flange  b.  There  is  no 
horizontal  face  to  swing  on,  and  if  the  boiler  flange  were  not 
parallel  with  the  face  of  the  header  tee  it  would  be  necessary  to 
make  a  bend  in  the  pipe  connection,  or  "spring"  it  by  pulling  up 
on  the  connection  bolts.  There  -is  no  other  detail  in  pipe  work 
erection  that  will  cause  as  much  trouble  from  joints  giving  out  as 
"sprung  connections,"  or  in  other  words,  forcing  two  flanges 


LIVE   STEAM   DETAILS.  I  19 

together  that  do  not  set  parallel,  by  drawing  up  hard  on  the  bolts 
and  compelling  the  pipe  work  to  spring  in  order  to  make  a  joint. 

The  connection  in  detail  A3~3,  Fig.  80,  though  quite  common,  is 
far  from  good  construction.  It  has  but  the  two  swings  at  joints  a 
and  b,  and  there  are  two  water  pockets,  one  at  each  leg  of  the  U. 
In  order  to  operate  such  a  connection  it  is  necessary  to  place  a 
drain  in  each  leg,  and  constant  attention  must  be  given  to  draining 
the  connection  before  opening  it  into  the  header.  If  the  U  is  made 
of  considerable  height  to  provide  for  expansion,  it  is  very  possible 
that  the  upper  portion  would  vibrate  to  such  an  extent  as  to  require 
anchoring,  due  to  the  fact  that  the  connection  projects  a  consider- 
able distance  from  its  supports.  The  amount  of  motion  that  any 


FIG.  80  (A3-3).  FIG.  81  A3~4). 

connection  will  permit  without  endangering  its  joints  is  determined 
almost  wholly  by  its  length  and  not  so  much  by  its  form. 

Connection  A3~4,  Fig.  81,  though  a  poor  detail,  has  fewer  faulty 
features  than  A3~3.  By  having  the  valve  next  to  the  header  it 
would  not  be  a  very  serious  matter  to  open  the  lower  valve  without 
draining  the  branch,  providing  it  was  opened  before  opening  valve 
next  to  header;  this,  however,  is  no  appreciable  advantage,  as 
" regular  operation"  sometimes  means  doing  the  wrong  thing  until 
some  serious  damage  is  caused.  There  are  only  two  swings  in  this 
connection  at  a  and  b.  . 

Connection  A3~5,  Fig.  82,  has  the  same  swings  and  general  con- 
struction as  detail  A3~2.  This  connection  is  shown  entering  the 
bottom  of  the  header  —  a  detail  which  is  open  to  some  criticism. 
There  are  many  who  believe  that  drips  from  the  header  will  return 
to  the  boiler  through  this  connection.  This  belief  is  shared  mostly 


120 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


by  the  operating  engineer,  who  argues  "We  get  rid  of  the  drips, 
where  else  can  they  go?"  It  is  hardly  correct  to  presume  that  the 
current  of  steam  which  because  of  its  high  velocity  carried  water 
into  the  header  would  later  on  permit  it  to  return  against  this  flow. 
Nor  is  it  possible  that  condensation  will  accumulate  in  the  header 
under  a  rapid  steam  flow  through  the  boiler  branches,  and  then 
return  when  the  velocity  becomes  less;  the  drips  cannot  accumu- 
late in  such  a  header,  nor  can  they  flow  along  the  header  to  some 
boiler  which  is  not  being  worked  hard,  as  the  drips  must  then  flow 
into  and  through  the  rapidly  flowing  steam. 

Since  water  of  condensation  cannot  accumulate  in  the  header 
without  flowing  with  the  incoming  steam,  there  is  but  one  path  for 


FIG.  82  (A3-5). 


FIG.  83  (A3-6). 


drips  to  take,  and  that  is  the  path  of  the  steam  entering  the  header 
and  flowing  to  the  engine.  The  mere  fact  that  the  header  is  dry 
does  not  indicate  that  condensation  has  been  returned  to  the  boilers; 
it  merely  proves  that  drips  do  not  stay  in  the  header  in  " pockets," 
but  keep  moving,  and  this  movement  is  toward  the  engines.  If 
this  is  to  be  the  method  of  discharging  drips,  it  would  be  quite  as 
safe  to  take  engine  branches  out  of  the  bottom  of  the  header  and 
keep  the  latter  constantly  drained  through  the  engine.  Or  in  other 
words,  do  not  try  to  separate  the  water  from  the  steam  —  a  course 
which  is  too  objectionable  to  be  considered ;  objectionable  not  only 
in  regard  to  steam  economy,  but  because  it  makes  it  impossible 
properly  or  economically  to  lubricate  the  pistons  under  such 
conditions. 

The  connection  shown  in  detail  A3~6,  Fig.  83,  is  objectionable, 
due  to  the  location  of  valve  at  a,  which  is  placed  at  a  consider- 


LIVE  STEAM   DETAILS.  121 

able  distance  from  the  line  of  supports,  bb.  The  corner  a  will 
vibrate  even  more  than  the  header,  due  to*  the  amount  of  weight 
that  is  free  to  move.  In  case  a  is  a  fitting,  it  will  also  be  liable  to 
vibrate  to  such  an  extent  as  to  require  stay  rods  run  to  some  support. 
In  designing  such  branches,  care  should  be  taken  to  keep  the  heavy 
portions,  such  as  valves  and  fittings,  either  near  to  the  boiler  or  to 
the  header,  or  to  such  parts  as  project  the  least  amount  beyond 
the  line  bb  of  pipe.  Pipe  work  that  requires  tie  rods  and  braces  to 
stay  the  branches  is  faulty  in  design. 

Detail  A3~y,  Fig.  84,  shows  what  oftentimes  cannot  be  avoided,  a 
long  branch  from  the  boiler  to  the  header.  In  case  the  connection 
is  made  as  shown  in  this  figure,  the  valve  at  the  boiler  should  be  at 


FIG.  84  (A3-7.) 

the  high  point,  and  entire  branch  from  the  valve  should  be  pitched 
toward  the  header  to  avoid  "water  pockets."  In  constructing  the 
branch  in  this  way  an  objectionable  feature  is  brought  into  the  con- 
nection which  may  justify  a  compromise,  a  choice  of  the  lesser  evil. 
With  the  valve  located  at  the  boiler,  the  entire  branch  would  be 
under  pressure  when  the  boiler  is  off,  and  this  would  constitute  a 
large  amount  of  condensing  surface.  In  case  any  joint  in  the 
branch  should  require  repairing  it  would  be  necessary  to  shut  down 
the  header  to  do  so.  To  place  a  valve  at  the  low  point  a  would 
be  inviting  trouble,  which  would  be  quite  sure  to  happen  if  the 
operator  should  forget  to  drain  off  the  branch  before  opening  it  into 
the  header.  If  it  is  possible  to  rise  up  from  header  and  make  a 
the  high  portion  of  the  branch,  then  the  valve  (or  valves,  if  two  be 
used)  should  be  located  at  this  high  point  and  all  possibility  of 
pocketing  water  will  be  avoided.  Ordinarily  this  would  be  best 
detailed  by  placing  a  right  angled  (square)  bend  on  top  of  the  tee 
and  locating  the  valve  at  the  upper  end.  The  valve  would  then  be 


122 


STEAM  POWER   PLANT  PIPING   SYSTEMS. 


FIG.  85  (A3-8). 


secured  against  vibration;  the  long  branch  from  the  boiler  to  the 

valve  should  have  a  gradual  pitch  from  the  boiler  up  to  the  valve. 
Detail  A3~8,  Fig.  85,  shows  an  almost  perfect  arrangement  for 

boiler  valves,  the  two  being  located  next  to  the  header  on  the  highest 
portion  of  the  branch.  The  valve  a  is 
the  shut-off  gate  valve,  valve  b  is  the 
automatic-stop  valve,  and  valve  c  is 
the  drain.  The  automatic  valve  can 
be  taken  apart  when  the  header  is  in 
operation.  Before  doing  so  the  leakage 
past  the  gate  valve  can  be  readily  ascer- 
tained through  valve  c,  and  if  it  is  too 
great  to  permit  working  on  the  automatic 
valve,  much  unnecessary  trouble  can 

be  averted.    The  valve  a  can  be  retained  as  the   tight  valve 

by   using   two  valves,  a   and    b,    and    it   should   be   opened   or 

closed  only  when  the  pressure  is  about  the  same  on  both  sides  of  it. 

The  drain  c  would  remove  any  condensation  lying  between  the 

valves,  but  to  avoid  trouble  in  case 

the  operator  should  neglect  to  open 

the   drain,    the    valves    should    be 

placed  as  near  together  as  possible 

to   reduce   the   pocket   to   smallest 

possible   amount.     The   mere    fact 

that  there  is  a  valve  at  each  end  of 

the    pocket   does    not    prevent    its 

filling  with  water,  as  it  is  next  to 

impossible  to  maintain  valves  abso- 
lutely tight.     The  leakage  continues 

to  condense  until  the  space  is  filled 

with   water.     The   drain   c   should 

discharge  into  an  open  funnel  so 

that  the  operator  can  see  and  hear  it  when  it  is  open.     This  drain 

c  is  extremely  useful  when  cleaning  a  boiler,  as  it  discharges  all 

condensation  out  of  the  branch  instead  of  permitting  it  to  run 

down  the  branch  onto  the  boiler  cleaner,  in  case  he  is  working 

under  a  steam  opening. 
The  connection  shown  in  detail  A3~9,  Fig.  86,  is  such  as  would 

be  used  in  case  the  header  were  located  below  the  opening  of  the 

boiler.    There  would  be  the  same  number  of  joints  between  the 


FIG.  86  (A3-9). 


LIVE  STEAM   DETAILS. 


123 


valves  and  the  header,  using  the  bend  shown,  as  would  be  used  with 
an  elbow,  as  shown  in  detail  A3~i.  The  only  difference  is  that 
more  radiating  surface  is  exposed  when  the  boiler  is  out  of  service. 
It  is  preferable  to  sustain  this  loss  rather  than  to  run  any  chances 
of  damaging  the  steam  machinery  by  water.  If  the  connection 
from  the  header  to  the  valves  can  be  made  with  one  length  of  pipe 
the  radiation  loss  will  be  quite  slight.  * 

The  connection  shown  in  detail  A3-io,  Fig.  87,  is  extremely  long, 
and  instead  of  making  it  as  shown  by  the  dotted  lines  there  would 
be  less  trouble  from  vibration  if  it  were  constructed  as  shown  by  the 
full  lines,  its  weight  being  kept  close  to  a  line  drawn  through  the 


FIG.  87  (A3-io). 


FIG.  88  (A3-n). 


supports.  The  far-projecting  bend  is  almost  invariably  a  badly 
vibrating  detail.  The  principles  of  detail  A3~io  may  be  carried 
out  with  gate  valves  also. 

The  connection  shown  in  detail  A3~n,  Fig.  88,  is  specially  suited 
for  the  systems  shown  in  the  previous  chapter,  in  which  the  mains 
or  headers  are  merely  by-passes  from  one  group  of  units  to  another. 
It  is  possible  with  this  system  to  isolate  one  or  all  of  the  units,  to 
run  No.  3  engine  unit  with  No.  i  boiler  unit,  or  run  all  as  one  sys- 
tem, the  header  being  an  equalizer,  and  only  a  small  portion  of  the 
total  steam  passing  through  it.  It  is  a  very  simple  undertaking  to 
repair  such  a  header  at  any  time,  the  only  loss  being  that  due  to 
running  each  unit  separately.  Tests  can  be  made  with  perfect  ease 
on  any  unit,  by  isolating  it  from  all  others.  But  one  extra  valve  is 
required  for  each  group  of  units.  If  for  any  reason  one  steam 
machine  can  be  worked  to  better  advantage  with  lower  steam  pres- 


124 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


sure,  this  condition  can  be  quite  readily  met.  With  this  arrange- 
ment one  unit  can  be  put  into  operation  without  making  use  of  any 
part  of  the  header. 

Class  A4-14  —  Live  Steam  Auxiliary  Main  and  Branches  to 
Pumps  and  Engines.  The  general  features  of  the  auxiliary  main 
deal  more  with  system  details  than  with  construction.  The  auxil- 
iary main  should  be  kept  sufficiently  far  from  the  steam  header 
to  allow  for  expansion  and  contraction  in  the  case  of  one  being 
cold  and  the  other  hot.  The  main  should  be  pitched  in  the  same 
direction  as  the  flow  of  steam,  and  provision  should  be  made  for 
draining  it. 

Fig.  89  (A4  to  14-1)  shows  the  auxiliary  main  with  an  opening 
at  the  top,  and  the  governor,  valves,  and  by-pass  so  arranged  that 
their  weight  will  be  easily  carried  by  the  main.  This  connection 


FIG.  89  (A4-i). 


FIG.  90  (A4-2). 


would  be  very  suitable  for  flanged  work.  By  taking  steam  out 
of  the  top  of  the  main  and  keeping  the  main  drained,  any  auxiliary 
can  be  immediately  started,  and  it  will  not  be  liable  to  stoppage 
or  dropping  off  in  speed  due  to  the  pump  filling  with  condensations 
Any  pump  or  engine  using  a  steam  governor  should  have  a  valve 
on  each  side  of  the  governor  and  one  in  the  by-pass,  also  a  throttle 
valve  at  the  pump.  A  valve  on  each  side  of  the  governor  is  neces- 
sary in  order  to  take  the  governor  apart  and  to  be  able  to  use  the 
pump  while  doing  so.  The  independent  throttle  is  necessary  to 


LIVE   STEAM   DETAILS.  125 

save  wear  on  the  stop  valves,  so  that  when  they  are  used  they  will 
close  tightly,  and  will  also  limit  the  speed  of  the  auxiliary  when 
the  automatic  valve  opens  to  its  fullest  extent. 

Fig.  90  (A4  to  14-2)  shows  a  very  satisfactory  arrangement 
for  branches  to  auxiliaries  not  requiring  a  regulating  valve.  The 
stop  valve  a  should  be  placed  next  to  the  main.  Stop  valves 
should  be  placed  in  every  branch  to  the  pumps,  etc.,  in  addition  to 
the  throttle.  The  throttle  valve  should  always  be  a  globe  or  an 
angle  valve  and  should  be  arranged  as  shown  so  that  it  can  be 
repaired  after  closing  the  stop  valve.  The  use  of  a  small  drain 
valve  at  b  is  both  unnecessary  and  undesirable.  The  drains  can 


FIG.  91  (A4-3).  FIG.  92  (A4~4). 

readily  be  worked  through  the  cylinder,  and  a  valve  at  this  point 
merely  adds  an  unnecessary  point  of  leakage.  Pump  builders  ordi- 
narily furnish  a  Y  at  end  of  steam  cylinders  with  an  outlet  on  a 
horizontal  plane  as  shown  in  detail  A4  to  14-3. 

Fig.  91  (A4  to  14-3)  may  be  preferable  to  Fig.  92  (A4  to 
14-4)  in  regard  to  its  manufacture,  but  in  almost  every  case  detail 
A4  to  14-4  can  be  used,  and  this  will  avoid  projecting  the  steam 
connection  far  from  the  pump.  It  will  make  a  difference  of  about 
12  in.  for  a  3-in.  steam  connection.  The  pump  builders  will 
furnish  detail  A4  to  14-4  if  specified  when  ordering  pumps. 

In  case  a  pressure  regulator  for  an  engine  governor  is  used,  as 
for  a  draft  fan,  the  governor  should  be  placed  at  a  considerable 
distance  from  the  engine,  or  there  should  be  provided  sufficient 
volume  between  the  engine  and  the  governor  so  that  the  cut-off 
of  the  engine  will  not  cause  the  governor  to  be  constantly  on  the 
move,  resulting  in  rapid  wear  and  requiring  a  great  deal  of  atten- 
tion; if  it  is  desirable  to  place  the  governor  close  to  the  engine, 
so  as  to  be  within  reach,  a  "receiver"  can  be  used  whose  volume 
is  about  equal  to  that  of  16  or  18  ft.  of  regular  size  steam  pipe. 

As  shown  in  Fig.  93  (A4-I4),  an  engine  having  a  2-in.  steam 
connection  would  require  a  receiver  say  of  4-in.  pipe  4  ft.  long  or 
6-in.  pipe  2  ft.  long.  A  receiver  is  not  necessary  for  a  pump,  due 


126 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


to  the  fact  that  a  pump  takes  about  the  same  amount  of  steam 
practically  all  the  time.  It  is  good  practice  to  make  the  governor 
flanged,  and  in  case  of  a  plant  using  two  or  more  engines,  to  have 
an  extra  governor  constantly  on  hand  and  in  good  order,  so  that 
instead  of  repairing  the  governor  in  position  it  may  be  taken  out 
and  replaced  by  the  governor  which  is  in  good  order.  Pump 
governors  are  almost  universally  installed  in  a  by-pass.  The  manu- 
facturer could  improve  this  feature  very  materially  if  he  would 


FIG.  93  (A4-5). 


FIG.  94  (A4-6). 


make  the  design  one  complete,  compact  unit,  as  shown  in  Fig.  94 
(A4  to  14-6),  with  a  strainer,  stop  valves,  by-pass,  and  flange 
connections. 

By  comparing  with  Figs.  89  (A4  to  14-1)  and  93  (A4  to 
14-5),  it  will  be  seen  how  compact  and  neat  such  a  device  can  be 
made.  There  are  various  types  of  steam  governors  used  for  pumps, 
draft  fan  engines,  etc.,  each  having  its  uses,  merits  and  faults.  The 
type  ordinarily  used  on  pumps  is  similar  to  Fig.  95  (A4  to  14-7); 
this  view  shows  a  self-contained  by-pass  as  part  of  the  governor. 

This  style  of  governor  serves  to  maintain  the  water  pressure 
constant,  regardless  of  steam  pressure,  the  steam  valve  being  prac- 
tically balanced.  The  water  pressure  and  spring  are  balanced  at 
the  normal  pressure.  This  is  the  type  of  governor  ordinarily  used 
for  fire  pumps.  It  is  not  suitable  for  feed  pumps  as  but  one  pres- 
sure is  maintained. 

Fig.  96  (A4  to  14-8)  shows  the  boiler  feed  pump    governor. 


LIVE  STEAM   DETAILS. 


127 


The  water  must  in  this  case  have  sufficient  pressure  in  excess  of  the 

steam  to  close  the  valve,  the  weight  increasing  this  resistance  as 

much  as  desired;  the  area  of  the  steam  valve  and  the  water  piston 

are  practically  the  same.     This  type  of  governor  will  maintain  the 

pressure  of  the  feed  water  say 

8   Ib.   above   steam    pressure, 

regardless  of  whether  the  steam 

pressure  is  60,  120,  or  180  Ib. 

This  is  very  essential  for  boiler 

feeding,  as  no  feed  valve  will 

stand  such  service  as  180  Ib. 

of  water  feeding  boilers  whose 

steam  has  dropped  say  to  100 

Ib.;  the  water  pressure  should 

drop  with  steam  pressure,  the 

excess    pressure     being    only 

sufficient  to  overcome  friction  FIG.  95  (A4-7). 

in  pipes  and  enabling  the  feed 

valves  to  be  left  fairly  well  open.     The  governor  shown  in  Fig.  97 

(A4  to  14-9)  is  oftentimes  used  as  a  pump  governor,  being  in 

reality  a  pressure  reducing  valve,  and  maintains  a  constant  fixed 

pressure  of  steam  in  the  cylinder. 


FIG.  96  (A4-8). 


FIG.  97  (A4-9). 


When  using  this  style  of   governor  a  gage  should  be  placed  on 
the  steam  branch  below  the  governor,  also  one  in  the  pump  dis- 


128 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


charge.  It  may  require  say  30  Ib.  of  steam  to  give  80  Ib.  of  water 
pressure  under  certain  conditions  of  the  pump,  and  by  repacking 
or  tightening  the  packing  it  may  require  50  Ib.  of  steam  to  balance 
80  Ib.  of  water.  This  change,  however,  is  not  frequently  made, 
and  whenever  it  is,  the  governor  must  be  reset.  This  governor 
has  the  advantage  of  having  no  pistons  and  stuffing  boxes,  which 
soon  cause  a  governor  to  stick  and  become  very  insensitive.  In 
other  words,  the  average  operation  of  this  type  is  more  satisfactory 
than  the  piston  or  stuffing  box  type.  The  same  governor, 
A4  to  14-9,  is  used  on  draft  fan  engines,  the  steam  flowing  in  the 
reverse  direction  to  that  shown.  The  pressure  of  steam  is  in 

this  case  balanced  by  the  spring,  and 
if  the .  pressure  rises,  the  draft  fans 
are  run  slower;  if  the  pressure  falls, 
the  spring  opens  the  valve  and  the 
draft  fan  engine  runs  at  higher  speed. 
This  type  of  governor  is  ideal  for  a 
draft  fan  engine  —  very  simple  and 
easily  regulated.  The  governor,  A4 
to  14-8,  can  be  modified  so  as  to 
eliminate  the  stuffing  box  and 
piston. 

Detail  A4  to  14-10,  Fig.  98,  shows 
the  governor  with  by-pass  arrange- 
ment. The  steam  valve  is  balanced 
and  when  water  and  steam  pressure 
are  the  same,  the  diaphragm  is 
balanced.  The  loading  of  the  spring 
must  be  overcome  by  the  additional 
pressure  of  water  over  that  of  steam. 
There  is  a  stuffing  box  at  the  hand 
wheel  stem,  but  there  is  no  move- 
ment at  this  point  except  when  the 
tension  of  the  spring  is  being  set.  The  by-pass  shown  in  this 
figure  is  much  preferable  to  detail  A4  to  14-6  as  it  permits  the 
governor  to  be  readily  disconnected  while  the  pump  is  running, 
and  at  the  same  time  leaves  the  pipe  work  perfectly  supported, 
which  is  not  the  case  with  detail  A4  to  14-5.  The  by-pass  shown 
in  detail  A4  to  14-10,  indicated  by  the  letter  a,  is  virtually  three 
valves  attached  to  the  one  valve  body.  The  diaphragm  and  tension 


FIG.  98  (A4-io). 


LIVE  STEAM  DETAILS.  1 29 

spring  are  both  protected  from  high  temperature  by  the  condensa- 
tion and  pump  water  in  the  lower  part  of  the  regulator.  The 
lower  tube  is  made  of  brass  to  aid  in  conducting  heat  away  from 
the  condensation.  This  governor  covers  the  requirements  for 
boiler  feed  pumps  in  all  particulars,  and  in  selecting  a  governor 
for  this  purpose  these  different  features  should  be  considered. 
The  tension  spring  has  a  nut  attached  at  each  end,  the  upper  end 
being  made  fast  to  the  valve  stem.  The  hand  screw  engages 
with  the  lower  nut,  and  for  boiler  feeding  would  put  a  tension  on 
the  spring.  If  lower  water  than  steam  pressure  is  required,  then 
the  spring  would  be  placed  under  compression.  For  example,  if 
60  Ib.  pressure  were  required,  and  the  boiler  pressure  were  120  lb., 
the  spring  would  be  loaded  so  that  the  water  pressure  would  be 
60  lb.  less  than  the  boiler  pressure.  If  a  fire  pump  is  to  be  used 
for  a  feed  pump  also,  this  governor,  detail  A4  to  14-10,  is  preferable 
to  the  devices  shown  in  detail  A4  to  14-17  with  stuffing  boxes, 
pistons,  etc.  The  latter  is  more  inferior  as  a  feed  pump  governor 
than  A4  to  14-10  is  as  a  fire  pump -governor. 

Fire  pump  governors  cannot  be  made  without  at  least  one  stuff- 
ing box  at  the  steam  valve  body.  Stuffing  boxes  cannot  be  made 
tight  unless  the  packing  is  forced  closely  together  and  close  to 
the  stem.  The  high  temperature  makes  the  packing  hard,  and 
ordinary  pressure  then  merely  presses  portions  of  packing  against 
the  stem;  to  make  old  packing  tight  it  must  be  forced  against  the 
stem.  Any  automatic  devices  such  as  governors,  etc.,  should  be 
entirely  free  from  stuffing  boxes  through  which  the  valve  is  auto- 
matically worked,  if  it  be  desired  that  same  shall  at  all  times  be 
sensitive. 

The  governor  shown  in  Fig.  99  (A4  to  14-11)  is  such  as  would 
be  used  for  the  steam  driven  air  and  circulating  pump,  controlled 
by  both  the  vacuum  and  the  steam  pressure  in  the  cylinders.  With 
no  pressure  in  the  pipe  to  the  pump,  the  tension  spring  would  open 
the  valve.  Assume  the  incoming  steam  to  be  at  120  lb.  pressure, 
and  spring  loaded  for  30  lb.  per  sq.  in.  If  the  pressure  to  the  pump 
then  is  30  lb.  without  any  vacuum  the  valve  will  close,  or,  if  the 
pressure  to  the  pump  is  15  lb.  and  the  vacuum  is  15  lb.,  the  valve 
will  close.  When  the  pressure  to  the  cylinder  is  20  lb.  and  vacuum 
10  lb.  the  valve  will  close.  This  type  governor  permits  a  certain 
speed  of  the  pump  for  each  varying  vacuum  pressure.  If  there  is 
no  vacuum  the  pump  will  not  be  allowed  to  run  away,  and  if  there 


130 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


is  the  highest  vacuum  the  pump  will  be  kept  in  motion.  This  is 
absolutely  necessary  in  order  to  maintain  the  vacuum.  It  will  be 
observed  that  this  device  would  necessitate  low  initial  pressure,  in 


FIG.  99  (A4-n). 


FIG.  ioo  (A4-I2). 


fact  lower  than  would  be  necessary  to  run  non-condensing,  unless 
an  extra  large  steam  cylinder  is  used. 

The  regulator  shown  in  Fig.  ioo  (A4  to  14-12)  can  be  used 
for  this  sen*ice,  and  it  allows  the  steam  pressure  to  the  pump  to  be 
what  it  will.  This  regulator  brings  in  the  objectionable  feature  of 
the  piston,  the  stem  passing  from  the  vacuum  chamber  to  the  steam 
chamber.  It  is  a  ground  joint  and  as  close  a  fit  as  can  be  made 
and  move  freely.  There  are  many  regu- 
lators made  on  this  plan,  and  the  claim 
for  them  is  that  the  leakage  is  small  and 
does  not  cause  an  outside  drip.  The 
spring  in  this  regulator  is  loaded  in  tension, 
so  that  proper  speed  will  be  obtained 
when  carrying  full  vacuum.  As  the 
vacuum  drops  or  the  pressure  rises  under 
the  diaphragm,  the  spring  draws  the  valve 
from  its  seat. 

This  same  style  of  valve,  Fig.  ioo,  is  used 
as  a  governor  to  maintain  a  constant  pres- 
sure higher  than  atmospheric  pressure. 
The  spring  then  is  in  compression  and 

the  valves  close  in  the  reverse  direction  from  that  shown.  In 
other  words,  the  increase  of  pressure  under  the  diaphragm  causes 
the  valve  to  close.  The  independent  crank  and  fly-wheel  dry 
vacuum  pump  is  ordinarily  supplied  with  a  fly-ball  centrifugal 


FIG.  ioi  (A4-I3). 


LIVE  STEAM   DETAILS.  131 

governor  and  a  small  air  cylinder  and  piston  that  act  upon  the 
governor  valve  in  conjunction  with  speed  control,  as  shown  in 
Fig.  101  (A4-I3). 

This  same  style  of  governor  is  also  used  for  air  compressors 
working  above  atmospheric  pressure.  This  style  of  regulation 
is  quite  satisfactory,  the  air  cylinder  comprising  only  a  partial 
control. 

Class  A15  —  Live  Steam  to  Stoker  Controller  and  Rams. 
There  is  another  feature  of  governing  that  will  require  considera- 
tion in  case  stack  fans  and  force-draft  fans  are  used.  An  installa- 
tion of  this  description  brings  into  consideration  numerous  details 
that  should  be  dealt  with  as  a  whole  and  not  separately.  For 
instance,  it  may  be  desirable  to  install  an  induced-draft  and 
fan  engine,  forced  draft  for  stokers  with  a  separate  engine,  and 
coal  feeding  mechanism.  It  has  been  customary  to  place  inde- 
pendent governors  on  each  of  these  three  drives  and  allow  any 
one  of  them  to  increase  or  decrease  in  speed  as  determined  by  its 
own  governor.  That  is,  the  fan  engine  may  slow  down  before  the 
coal  feed  or  air  blast  engine  and  cause  furnaces  to  discharge  gases 
out  of  the  fire  doors,  etc.  Again  the  coal  feed  may  speed  up  before 
the  air  blast,  causing  a  waste  of  the  gases;  or  the  air  blast  may 
speed  up  without  coal,  causing  loss  of  heat  units  in  heating 
useless  air. 

These  three  elements  should  have  a  better  system  of  control 
than  a  separate  governor  for  each.  When  one  is  increased  they 
should  all  three  be  increased,  and  vice  versa.  The  governor  should 
control  all  three.  One  steam  governor  to  increase  or  decrease 
the  pressure  for  the  three  would  be  wholly  useless.  This  is  a 
peculiar  condition  to  contend  with  for  the  reason  that  no  present 
form  of  governing  will  properly  meet  this  condition  and  it  is  a  con- 
dition that  very  materially  affects  the  efficiency  of  the  plant. 
Assume  that  the  pressure  is  very  high  and.that  the  three  services  are 
running  at  their  extreme  low  speed.  Now  undertake  to  adjust  the 
fan  governor  to  run  the  engine  at  such  a  speed  that  it  will  just 
allow  the  pressure  over  the  grates  to  be  atmospheric  pressure,  or  say 
one-tenth  inch  of  water  by  the  draft  gage.  Note  the  quantity  of  air 
and  adjust  the  coal  feeder  accordingly;  there  are  then  the  three 
elements  working  in  a  most  economical  manner.  Leave  the  gover- 
nors as  adjusted  and  allow  the  plant  to  run  up  to  full  capacity 
and  then  note  the  conditions  again.  It  may  be  found  that  the 


132 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


steam  pressure  is  about  10  Ib.  lower  than  usual,  the  blast  fan  is  run- 
ning at  a  frightful  speed,  stokers  are  running  at  a  good  speed,  and 
the  stack  fan  has  not  increased  as  much  proportionately  as  the  other 
two.  The  operating  conditions  are  wretched,  showing  poor  econ- 
omy, furnaces  smoking,  blast  engine  fairly  pounding  itself  to 
pieces  —  and  for  all,  the  governors  are  working  "perfectly";  the 
fault  lies  in  the  system  of  governing. 

It  is  unreasonable  to  expect  three  governors,  possibly  of  differ- 
ent size  or  make,  and  for  three  entirely  different  services,  to  "meas- 
ure" out  the  requisite  steam.  To-day,  when  running  one-quarter 
capacity,  the  fan  engine  may  want  50  Ib.  of  steam  per  hour  to 
maintain  the  proper  speed  to  discharge  the  gases  corresponding 
to  one-quarter  capacity.  The  blast  engine  may  want  65  Ib.  and 
stoker  drive  20  Ib.  For  one-half  load  the  requisites  may  be  70, 
90,  and  30  Ib.  respectively,  and  for  full  load  85, 115  and  45  Ib.  Any 
of  the  three  requirements  would  be  varied  by  tightening  the  pack- 
ing, or  making  any  other  adjustments. 

The  ordinary  governors  are  adjustable,  so  that  a  certain  delivery 
of  steam  will  be  obtained  at  the  particular  pressure  set.  For  any 
other  pressure  the  steam  discharge  may  be  almost  any  amount, 
and  whatever  it  is,  the  operator  cannot  control  it  in  any  way.  The 

governor,  to  be  suitable  for  such 
service,  should  be  so  constructed 
that  it  will  permit  a  flow  of  a  cer- 
tain number  of  pounds  of  steam 
per  minute  at  lowest  pressure,  and 
should  be  adjustable  also  for  a 
certain  volume  at  the  higher  pres- 
sure. Such  a  governor  is  not  on 
the  market.  Without  it  no  three 
machines  or  even  two  machines 
can  be  worked  economically  except 
at  one  particular  rate  of  coal  con- 
sumption. There  are  two  methods  of  arranging  this  style  of 
governing.  One  is  to  arrange  the  governors  so  that  their  range 
as  well  as  their  normal  pressure  can  be  adjusted.  This  detail  is 
shown  in  Fig.  102  (Ai5~i). 

Ordinarily  the  spring  a  would  be  the  spring  to  balance  the 
desired  steam  pressure.  By  having  a  counteracting  spring  b,  the 
movement  of  the  valve  stem  through  the  range  of  pressures  can 


Fio.  102  (Ais-i). 


LIVE   STEAM   DETAILS.  133 

be  varied  greatly.  For  instance,  if  the  tension  is  taken  off  spring 
b,  the  travel  of  the  valve  stem  may  be  one-quarter  inch  while 
steam  pressure  is  varied  between  150  and  160  Ib.  When  tension 
is  put  on  spring  b,  additional  strain  would  be  required  on 
spring  a.  By  increasing  the  strain  on  both  springs  the  travel 
of  the  stem  for  10  Ib.  variation  may  be  reduced  to  y1^-  inch  or 
even  less. 

The  other  method  of  governing  is  as  shown  in  Fig.  103  (A  15-2). 
The  stack,  blast,  and  stoker  motors  would  each  have  a  rolling  type 
of  valve  with  a  slotted  lever,  and  a  rock  shaft  which  would  also 
have  slotted  levers.  The  shaft  would  be  rolled  by  means  of  a 
standard  damper  regulator,  the  shaft  being  located  possibly  at  the 
upper  portion  of  the  boiler  front.  Each  of  the  three  valves  can  be 
separately  set  for  low  speed  and  high  speed  conditions.  The  speed 
changes  would  be  effected  simultaneously  on  all  three  valves.  The 
damper  regulator  can  be  set  so  that  within  3  Ib.  variation  the  en- 
gines may  be  running  from  no  load  to  full  load.  This  arrangement 
would  be  far  more  reliable  and  sensitive  than  separate  governors. 
In  case  natural  draft  is  used  instead  of  a  stack  fan,  then  the  rock 
shaft  would  operate  the  dampers  instead  of  the  stack  fan  engine. 
Counterweights  would  be  placed  on  the  valve  levers,  keeping  all 
lost  motion  out  of  the  parts,  and  enabling  them  to  be  made  in  a 
comparatively  crude  way. 

An  accurate  system  of  regulating  furnace  auxiliaries  will  save 
not  less  than  5  per  cent  of  the  fuel,  and  for  a  plant  of  3,000  kw. 
a  saying  of  5  tons  per  day  at  $1.50,  or  $2,750  per  year  would  be 
shown.  The  system  shown  in  detail  A4-I5,  Fig.  103,  would  cost 
possibly  $100  more  than  independent  governors,  and  would  involve 
some  study  and  trouble  for  the  engineer.  The  valve  for  this  work 
should  be  of  the  corliss  type,  with  the  engine  lubricator  placed 
above  it,  so  that  the  valve  also  would  be  lubricated.  The  valve 
shown  in  Fig.  104  (Ai5~3)  would  be  very  suitable. 

This  valve  requires  more  effort  to  open  than  a  balanced  valve, 
but  it  closes  much  tighter,  and  since  there  is  ample  power  avail- 
able with  the  damper  regulator,  a  valve  such  as  is  shown  in  detail 
A 1 5-3,  that  opens  and  closes  slowly,  is  much  easier  to  adjust  and 
will  stay  adjusted.  Any  valve  of  the  globe  valve  type  opens  too 
quickly  for  close  regulation.  This  valve  is  the  standard  "throttle 
valve"  with  a  slotted  lever  instead  of  a  hand  lever.  The  by-passes 
and  valves  permit  any  one  of  the  three  machines  to  run  temporarily 


134 


STEAM  POWER  PLANT  PIPING  SYSTEMS 


FIG.  103  (Ais-2). 


FIG.  104  (Ais-3). 


FIG.  105  (Ais-4). 


LIVE   STEAM   DETAILS. 


135 


at  a  higher  or  lower  speed,  and  at  the  same  time  the  fixed  regula- 
tion is  not  altered. 

The  steam  lines  to  an  underfed  type  of  stoker  should  never  be 
buried,  but  may  be  placed  in  a  trench,  as  shown  in  Fig.  105 
(Ai5~4.),  which  arrangement  is  satisfactory  if  the  trench  is  well 
drained.  If  the  drainage  is  poor  any  water  such  as  waste  from 
wetting  down  ashes  will  collect  in  the  trench  and  be  evaporated  on 
contact  with  the  live  steam  pipes,  the  steam  thus  formed  interfering 
with  the  work  of  the  attendants. 

The  steam  pipes  for  the  stokers  should  not  be  covered  in  any 
way  and  the  supports  should  be  such  as  will  permit  of  free  expan- 
sion and  contraction.  With  the  trench  as  shown  in  the  figure  a 
set  of  cover  plates  as  also  shown  should  be  used.  The  drawing 
shows  the  cast-iron  cover  plate  supported  on  angle  irons.  If  there 
is  a  basement  under  the  boiler  room  the  stoker  steam  mains  can 
easily  be  supported  under  the  floor. 

To  obtain  the  best  results  with  steam  stokers  it  is  advantage- 
ous to  arrange  the  piping  so  that  there  will  be  a  downward  flow 
from  the  feed  mains  to  the  piston  cylinders  and  through  the 
exhaust.  This  detail  necessitates  the  placing  of  the  steam- 
controlling  valve  above  the  steam  line  to  the  stoker  rams,  and  the 
exhaust  main  below  the  cylinders.  If  the 
same  main  is  used  for  steam  and  exhaust 
alternately  it  should  be  placed  below  the 
cylinders  with  the  steam-controlling  valve 
above  and  the  exhaust-controlling  valve 
below.  To  avoid  water  hammer  in  the 
pipe  line,  the  drips  should  at  all  times  have 
a  downward  flow  and  those  drips  collected 
in  the  low  down  main  should  be  dis- 
charged at  the  low  point,  even  though  the 
exhaust  is  made  from  a  higher  level. 

Class  A16  —  Live  Steam  to  Tank  Pump. 
In  feeding  steam  to  the  cylinders  of  tank 
pumps  it  is  often  possible  to  use  the  type 
of  pump  controller  shown  in  Fig.  106 
(Ai6-i),  which  is  more  satisfactory  than 


FIG.  106  (Ai6-i). 


a  pressure-operated  governor.  By  referring  to  the  illustration  it 
will  be  seen  that  this  type  of  controller  consists  of  a  needle  valve, 
operated  by  a  cable  connected  with  a  float  in  the  elevated  tank. 


136 


STEAM   POWER   PLANT  PIPING   SYSTEMS. 


The  needle  valve  used  should  be  of  the  slow-opening  type  of 
globe  valve.  In  order  to  provide  for  operation  of  the  pump 
independent  of  the  float  it  is  desirable  to  run  a  by-pass  around  the 
controller 'valve. 

The  arrangement  01  governor  construction  just  described  per- 
mits the  pump  to  be  run  at  speeds  varying  directly  with  the  quantity 
of  water  or  oil  in  the  tank.  It  also  furnishes  the  desirable  feature 
of  keeping  the  pump  in  operation  at  nearly  all  times,  thus  prevent- 
ing interruptions  from  condensation.  The  telltale  shows  the 
level  of  the  fluid  in  the  tank,  even  though  the  operation  of  the  valve 
and  its  counterweights  is  interrupted.  For  installations  where 
the  storage  tank  is  located  at  some  distance  from  the  pump,  or 
where  the  pump  is  required  to  deliver  water  for  other  purposes  and 
at  different  pressures,  it  may  be  found  advisable  to  place  a  float 
valve  at  the  tank  to  shut  off  the  supply  and  use  a  pressure  regulator 
to  control  the  steam  to  the  pump. 

Class  A17  —  Live  Steam  to  Smoke  Consumer  or  Oil  Burner. 
The  piping  for  steam  to  smoke  consumers  or  oil  burners  would 
come  under  class  A-iy,  but  these  details  will  not  be  considered 
here;  a  smoke  consumer,  by  reason  of  the  destructive  effects  on 
boilers,  should  be  used  only  in  exceptional  cases;  oil  burners  are 
installed  by  their  manufacturers  and  the  piping  laid  out  more 
according  to  builder's  details  than  general  piping  designs. 

Class  A18  —  Live  Steam  to  Soot  Blowers.  In  arranging  the 
piping  for  soot  blowers  the  steam  should  be  taken  from  a  separate 
main  and  not  from  the  boiler.  The  independent  supply  is  quite 

necessary  in  order  to  enable  the 
clearing  of  the  tubes  of  a  boiler 
when  it  is  out  of  service.  Open- 
ings for  soot  blowers  should  be 
provided  at  the  sides  of  the  boilers. 
The  detail  design  and  arrangement 
of  the  soot  blower  piping  are 
shown  in  Fig.  107  (Ai8-i).  The 
branch  main  for  the  steam  supply 
to  the  blower  should  be  strongly 


FIG.  107  (AI&-I). 


supported  so  that  it  may  withstand  the  hard  pulls  and  jerks 
of  the  operator.  A  quick-closing  valve,  located  as  shown  in 
Fig.  107,  will  partially  relieve  the  hose  of  the  pressure  while  blow- 
ing and  entirely  cut  off  the  steam  when  the  blower  is  being  moved 


LIVE   STEAM   DETAILS.  137 

from  one  part  of  the  boiler  to  another.  This  quick-opening  valve 
should  be  attached  to  the  hose  and  not  be  a  portion  of  the  fixed 
piping;  the  tight-closing  valve  as  shown  should  be  used  only  as  a 
stop  valve,  since  if  it  were  used  as  a  throttle 'it  would  soon  become 
leaky.  Any  slight  leakage  in  the  balanced-lever  valve  will  not 
interfere  with  the  operation  of  the  cleaner. 

The  subject  of  soot  cleaning  appears  quite  simple,  but  neverthe- 
less there  are  many  plants  running  on  very  poor  economy  because 
they  cannot  clean  soot  and  deposit  from  the  tubes.  It  is  no  uncom- 
mon thing  to  find  5oo-hp.  water-tube  boilers  set  with  a  3  to  4-ft. 
passageway  and  tiled  for  vertical  passes.  The  outside  measure- 
ment of  such  boilers  is  about  twelve  feet.  Good  economy  can  be 
secured  with  vertical  passes  only  when  ample  provision  for  cleaning 
is  provided.  Horizontal  passes  permit  the  use  of  long  blower  tubes 
operated  from  front  and  possibly  the  rear  of  the  boiler  setting, 
thus  enabling  much  more  thorough  cleaning  where  it  is  necessary 
to  place  wide  boilers  with  narrow  alleyways. 

Class  A19  —  Live  Steam  By-Pass  to  Exhaust  Heater  or  Heating 
System.  A  steam  by-pass  to  the  exhaust  heater  or  heating  system 
is  provided  to  furnish  live  steam  to  the  exhaust  heater  when  there 
is  but  little  exhaust  and  high  temperature  water  is  desired.  The 
valve  shown  in  Fig.  97  (A4-g)  can  be  used  for  this  service  with 
the  steam  flow  as  shown.  Such  a  valve  should  be  small  and  have 
a  very  large  diaphragm.  A  light  spring  should  be  used  to  balance 
a  pressure  of  say  i  or  2  Ib.  per  square  inch  on  the  diaphragm. 
Ordinarily  when  there  are  differences  in  pressure  of  from  2 
to  1 60  Ib.,  it  is  found  more  satisfactory  to  use  two  regulators  of 
the  same  design,  one  reducing  to  about  60  Ib.  and  the  other  to  the 
pressure  on  the  heater. 

There  is  a  rather  peculiar  feature  in  connection  with  machinery, 
the  back  pressure  steam  from  which  is  used  for  heating  water  or 
buildings:  When  the  demand  for  low  pressure  steam  increases  the 
back  pressure  is  reduced,  at  the  same  time  the  amount  of  steam 
being  delivered  by  the  machine  is  also  reduced.  When  less  steam 
is  being  condensed  in  the  heating  system  the  back  pressure  rises 
and  thus  compels  the  engines  to  take  more  steam  to  perform  the 
same  work.  This  wastes  steam  to  the  atmosphere.  The  heater 
control  should  be  such  that  when  the  back  pressure  drops,  the 
engine  should  take  more  steam  and  when  the  back  pressure  rises, 
the  engine  should  take  less  steam,  this  being  the  reverse  of  the 


138 


STEAM   POWER   PLANT  PIPING  SYSTEMS. 


FIG.  108 


usual  practice.  In  other  words,  when  the  back  pressure  tends  to 
rise,  the  engine  should  be  allowed  to  exhaust  to  the  atmosphere 
and  be  relieved  of  all  back  pressure,  and  the  pressure  on  the  heater 
should  be  allowed  to  drop  before  the  engine  exhaust  is  again  dis- 
charged into  the  heater  system.  Thus  the  amount  of  steam  used 
from  the  engine  would  be  reduced. 

In  Fig.  108  (Aig-i)  is  shown  a  valve  arranged  to  perform  these 
duties.     When  the  valve  is  open  to  the  atmosphere  the  weight 

exerts  a  pressure  per  square  inch 
of  say  2  Ib.  against  the  heater 
pressure  and  when  the  valve  is 
down  it  exerts  a  pressure  of  4  Ib. 
against  the  port  to  the  atmosphere. 
This  range  may  be  increased  say 
from  6  Ib.  back  pressure  to  i  Ib. 
heater  pressure  by  positioning 
the  lever  on  the  valve  stem  and 
by  varying  the  location  of  the 
weight  on  the  lever.  Such  a 
valve  enables  the  engine  to  exhaust 

to  the  atmosphere  all  the  steam  that  a  heater  or  heating  system 
does  not  condense.  The  valve  is  now  on  the  market,  being  used 
as  an  atmospheric  valve  in  connection  with  a  condenser,  the  con- 
denser taking  the  place  of  the  heater  as  shown.  The  lever  should 
roll  on  a  rock  shaft  similar  to  that  shown,  so  that  the  weight  will 
neither  pass  nor  stand  over  the  center  of  this  shaft.  If  this  valve 
is  adjusted  so  that  it  closes  against  atmospheric  pressure  at  3  Ib., 
then  the  live  steam  by-pass  should  be  set  to  be  open  only  on  pres- 
sure below  2  Ib.  This  will  avoid  blowing  live  steam  into  the 
heater  while  the  engine  is  exhausting  to  the  atmosphere. 

Class  A20  —  Live  Steam  to  Whistle.  Whistle  connections  cause 
considerable  annoyance  due  to  condensation  accumulating  in  the 
p^pes  before  the  whistle  is  used.  The  connection  shown  in 
Fig.  109  (A20-i)  will  allow  condensation  to  accumulate  at  the 
top  of  the  valve  and  requires  blowing  through  the  whistle  before 
the  tone  is  right. 

The  connection  shown  in  Fig.  109  (A2o-2)  necessitates  a  hole 
through  the  roof  for  the  whistle  cord  and  allows  considerable  con- 
densation of  steam  in  the  pipe,  which  is  especially  undesirable  if 
the  pipe  is  long. 


LIVE  STEAM   DETAILS. 


139 


The  latter  style  of  whistle  connection  is  quicker  to  operate  and 
produces  the  correct  tone  as  soon  as  opened,  but  for  a  long  run  of 
pipe  the  detail  shown  in  Fig.  109  (A2O-3)  will  be  found  more 
satisfactory  as  it  allows  the  whistle  valve  to  be  placed  low  down,  and 


(A20-i)  (Aao-2)  (Aao-3) 

FIG.  109. 

the  upper  pipe  to  be  well  drained  until  the  steam. valve  is  opened. 
The  drain  closes  simultaneously  with  the  opening  of  the  steam 
valve. 

Class  A21  —  Live  Steam  to  Ejector  Vacuum  Traps.  The  steam 
branch  to  an  ejector  vacuum  trap  is  for  the  purpose  of  breaking  the 
vacuum  and  discharging  the  condensation.  There  is  considerable 
mechanism  in  these  devices  because  they  contain  automatic 
features  which  permit  the  steam  to  blow  out  condensation  imme- 
diately following  the  closing  of  the  vacuum  drip  line  to  the  trap. 
The  piping  details  of  ejector  vacuum  traps  have  no  special  piping 
features. 

Class  A22  —  Live  Steam  to  Heating  System.  The  steam 
required  for  a  heating  system  would  not  ordinarily  be  very  extensive 
in  a  power  station,  but  in  case  heat  is  to  be  provided  for  car  shops 
and  neighboring  buildings  some  special  arrangement  in  station 
piping  system  and  machinery  may  be  made  so  that  exhaust  steam 


140  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

will  be  available  and  can  be  used  for  heating.  This  will  be  taken 
up  under  the  details  to  be  later  considered  in  Class  C. 

Live  steam  heating  should  be  avoided  wherever  possible.  The 
high  pressure  of  the  steam  causes  leaks  at  stuffing  boxes,  joints  and 
similar  connections  that  will  give  no  trouble  at  low  pressures. 
To  stand  high  pressures  the  heaters  must  be  in  the  shape  of  pipe 
coils,  and  if  steam  at  160  or  170  Ib.  be  used  it  is  liable  to  injure 
whatever  it  comes  in  contact  with.  However,  for  a  condensing 
plant  there  is  no  other  system  suitable  if  there  are  but  one  or  two 
rooms  to  be  heated.  Exhaust  steam  from  auxiliaries,  when  piped 
to  a  heater,  is  not  sufficient  in  amount  to  maintain  a  pressure  which 
will  allow  the  distribution  pipes  to  be  of  any  considerable  length. 
The  rooms  to  be  heated  are  generally  the  chief  engineer's  office, 
lavatory,  stock  room  and  an  oil  room.  The  use  of  electric  heaters 
would  not  be  justified  because  the  cost  of  their  installation  would 
equal  steam  heaters  and  the  cost  per  B.t.u.  of  radiation  would  be 
possibly  50  times  that  of  steam  heating. 

If  there  are  but  three  or  four  rooms  to  be  heated  there  is  prac- 
tically no  better  method  in  a  condensing  plant  than  to  use  live 
steam.  The  temperature  can  be  regulated,  as  shown  in  Fig.  no 
(A22-i),  by  allowing  more  or  less  air  to  remain  in  the  heater. 
The  air  will  lie  below  the  steam  and  just  above  the  condensation. 
The  drips  from  the  heating  coils  should  discharge  to  the  atmos- 
pheric exhaust  line.  This  discharge  will  save  the  water  of  high 
temperature,  together  with  any  leakage  of  steam  passing  the  trap, 
and  avoid  difficulties  attendant  upon  exhausting  drips  to  a  sewer, 
which  practice  not  only  injures  the  sewer  but  causes  steam  to 
leak  from  the  catch  basins. 

The  coils  should  be  laid  out  so  that  the  pipes  will  run  into  a 
corner  and  return,  allowing  free  expansion  and  contraction.  Such 
expansion  is  very  severe  in  a  stiffly  connected  live  steam  heater. 
The  corners  should  be  made  of  pipe  bends,  but  bends  for  connect- 
ing purposes  will  necessitate  unions  at  either  end  of  each  pipe. 
A  simpler  method  is  to  use  elbows  and  right  and  left  thread  con- 
nections in  the  short  return. 

Another  method  of  regulating  the  temperature  of  a  live  steam 
heater  is  as  shown  in  Fig.  no  (A22-2).  In  this  arrangement 
the  steam  valve  is  a  hand  controlled  throttle;  the  drip  valve  has  a 
very  small  hole  drilled  through  the  disk.  While  in  operation  the 
drip  valve  is  kept  closed,  the  discharge  of  drips  being  through  the 


LIVE  STEAM   DETAILS.  141 

small  drilled  hole.  The  principle  of  this  detail  is  more  complex 
than  it  would  at  first  sight  appear.  For  every  varied  amount  that 
the  steam  valve  is  opened  a  balance  is  established  in  the  heater 
coil.  By  increasing  the  opening  of  the  steam  valve  a  greater  pres- 


FIG.  no  (A22-i,  2). 

sure  is  exerted  in  the  heater,  and  a  greater  quantity  of  drip  is  dis- 
charged through  the  lower  valve.  The  condensation,  or  air,  is 
discharged  until  the  increased  heating  or  condensing  surface 
reduces  the  pressure  in  the  heater,  simultaneously  reducing  the 
drain  through  the  lower  valve.  When  the  upper  valve  is  further 
closed  the  pressure  in  the  heater  is  reduced,  the  discharge  at  the 
lower  valve  is  retarded  until  the  heating  or  condensing  surface 
has  been  reduced  by  increased  condensation  to  the  point  where 
the  pressure  is  about  to  raise  and  increase  the  flow  of  drip. 

Class  A23  —  Live  Steam  Cleaner  for  Oil  Tanks.  The  branch 
from  which  live  steam  is  drawn  to  clean  the  accumulation  from 
storage  oil  tanks  is  seldom  used  and  therefore  should  have  a  stop 
valve  as  close  to  the  steam  main  as  possible.  Steam  is  used  to 
raise  the  temperature  of  the  tank  cleaning  water,  so  that  the 
grease  and  precipitation  can  be  removed  from  the  sides  and 
bottom  and  easily  washed  out  of  the  tank.  The  simple  method 
of  piping  for  the  tank  supply  is  shown  in  Fig.  in  (A23~i). 
The  hose  is  connected  to  a  valve  next  to  the  ejector  tee  which 
operates  as  a  mixer.  The  cleaner  is  made  of  a  length  of 
pipe  with  a  wire  brush  attached  at  the  lower  end  and  a  nozzle 
from  the  pipe  adjusted  to  discharge  the  steam  and  water  on  the 
brush.  This  device  offers  a  quick  method  for  loosening  and 
washing  the  gum  and  grease  from  the  shells  of  oil  tanks.  The 
hose  need  not  be  wire-wrapped  because  it  is  not  under  very 
high  pressure,  possibly  15  or  20  Ib.  The  brush  can  be  secured 
to  the  bent  pipe  as  shown  in  Fig.  112  (A23-2).  The  upper 


142 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


portion  of  the  handle  should  be  of  pipe  with  its  lower  end 
forged  solid. 

Class  A24  —  Live  Steam  from   Header   to  Atmosphere.     It   is 

not  customary  to  install  a  steam  blow-off  from  a  header  to  the 
atmosphere.  For  this  reason  it  often  is  necessary  to  reduce  the 
pressure  on  the  header  by  blowing  off  through  some  engine.  If 
the  header  is  divided  into  three  sections,  each  section  should 
have  a  blow-off  not  less  than  1.5  in.  in  diameter  run  through  the 


y'ST£#rt 


FIG.  in  (A23-i). 


FIG.  112  (A23-2). 


roof.  Repairs  to  the  steam  main  can  be  made  much  more 
readily  if  there  is  a  means  of  quickly  relieving  the  pressure  on  a 
damaged  section. 

Class  A25  —  Live  Steam  to  Damper  Regulator.  The  steam 
line  which  feeds  a  damper  regulator  is  ordinarily  designed  to 
transmit  the  pressure  in  the  main  to  the  weighing  device  of  the 
regulator.  This  line  should  be  tapped  from  a  drip  pocket  or 
the  bottom  of  the  header,  so  that  condensed  water  will  be 
delivered  to  the  regular  pipe  instead  of  steam.  If  the  valve 
at  the  regulator  were  leaking  badly  at  a  stuffing  box,  the  small 
pipe  would  then  not  be  able  to  condense  fast  enough  to  supply 
water  to  the  leak.  This  would  allow  live  steam  to  come  in  con- 
tact with  and  injure  the  rubber  diaphragm.  Such  damper  regula- 
tor diaphragms  are  made  to  stand  the  boiler  pressure,  but  they 
will  not  stand  the  temperature  of  steam  at  boiler  pressure. 

Class  A26  —  Live  Steam  to  Oil  Filter.  Steam  is  often  fed  to  a 
filter  so  that  more  rapid  work  can  be  done  by  a  filter  which  is  of 
too  small  capacity.  It  is  often  found  that  oil  is  very  stiff  when 
cool  and  requires  heating  in  order  to  enable  it  to  pass  through 
the  filter.  The  oil  when  in  this  condition  is  "too  fat,"  and  has 


LIVE  STEAM   DETAILS.  143 

been    made    so    by  the  addition    of    considerable    cylinder   oil 

returning  with  the  drips.     The  correct  remedy  for  such  a  con- 

dition is  to  remove  the  excess  fats  by  allowing  the  oil  to  stand, 

when   the   impurities  will   precipitate.     If  the  filtering  arrange- 

ment  is   amply  large  and    the   oil   is  in  good  condition,  better 

results  are  obtained  by  keeping  the  oil  as  cool  as  it  can  be  freely 

handled  in  the  pipe  lines.     The  better  method  is  to  place  the 

filter  in  a  warm  place  and  not  to  use  a  steam   heater  in   the 

filter.     The  room  where  the  filter  is  to  be  placed  should  have  a 

temperature    of    70°  F.,    and 

the  filter  bed    should    be    of 

ample   dimensions   for   oil  to 

pass  through  without  forcing. 

A  simple  heater,  as  used  for 

filters,  is  as  shown  in  Fig.  113 

(A26-i).     This    view    shows 

valves  at  both  the  inlet   and 

the  outlet,  but  it  is  somewhat 

safer    to    use    a   valve    as    a  FIG.  113  (A26-i). 

throttle  at  the  inlet  side  only, 

leaving  the  other  end  free  to  drip  into  the  sewer.      The  coil 

when   placed   is   pitched   slightly   downward,   having   the   outlet 

about  2  in.  lower  than  the  inlet.     Such  a  coil  can  readily  be 

removed  and  is  well  supported. 

Class  A27  —  Live  Steam  to  Blow  out  Oil  Drip  Main.  A  steam 
branch  is  led  to  the  oil  drip  main  for  the  purpose  of  cleaning  it 
and  can  be  arranged  as  shown  in  Fig.  114  (A27~i).  The  steam 


a        i   a 


FIG.  114  (Aay-i). 

line  should  connect  with  the  drip  main  through  a  syphon  tee 
with  a  water  connection  below.  The  steam  and  the  water  should 
each  be  controlled  by  separate  valves  with  the  syphon  tee  located 
somewhat  higher  than  the  drip  main.  The  main  should  have 
two  discharge  valves,  one  to  a  filter  and  one  to  the  outside  of  the 
building.  Each  engine  branch  should  connect  with  the  drip 


144 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


main  through  a  valve.  The  drip,  steam  and  water  branches 
should  be  sufficiently  elastic  to  allow  for  free  expansion  and  con- 
traction of  the  drip  main.  The  end  projecting  beyond  the  build- 
ing should  be  threaded  so  that  the  line  can  be  extended  when  it 
is  to  be  blown  out.  The  drip  line  should  blow  to  the  atmosphere 
so  that  the  steam  may  escape  and  thus  avoid  blowing  the  grease 
and  gum  into  the  drainage  system.  Blowing  the  drip  main  to  the 
atmosphere  also  furnishes  a  means  for  observing  the  condition 
of  the  wash  water. 

Class  A28  —  Live  Steam  to  Water  Column  and  Column  Con- 
nections.   The  steam  connection  to  a  water  column  is  often  made 

with  bends  and  elbows,  thus 
providing  no  facilities  for  in- 
spection. Even  though  the 
steam  connection  is  not  liable 
to  scale  or  become  blocked, 
it  is  certainly  safer  and  more 
in  line  with  good  operating 
practice  to  be  able  to  know 
positively  that  the  steam 
branch  is  clear.  The  con- 
nection shown  in  Fig.  115 
(A28-i)  has  the  steam  and 
water  connections  made  with 
cross  and  plugs.  The  plugs 
should  be  long  threaded  and 
made  of  solid  brass.  The 
column  shown  is  faced  for 
flanged  connections  and  for  at- 
taching a  supporting  bracket. 
The  column  manufacturer 
will  furnish  the  water  col- 
FIG.  115  (A28-i).  umn  faced  for  flanges  and 

provided     with      a     bracket 

suitable  for  attaching  to  the  boiler  front.  For  high  pressure 
work  a  flanged  connection  is  the  only  satisfactory  way  of  attach- 
ing the  water  column.  By  supporting  each  column  free  from 
the  pipe  work  a  better  line  is  kept,  the  piping  is  more  secure,  and 
pipe  can  be  disconnected  without  disturbing  the  columns  or  their 
connections. 


LIVE  STEAM   DETAILS. 


'45 


Such  connection  pipes  as  pass  through  the  boiler  settings 
should  be  protected  by  pipe  sleeves  two  sizes  larger  than  the  con- 
nection pipes.  Pipe  if  in.  in  diameter  is  generally  used  for  con- 
necting water  columns,  the  duty  being  practically  the  same  for 
any  size  boiler.  If  the  connections  are  more  than  3  ft.  in 
total  length  the  column  should  be  separately  supported,  and  if 
separately  supported  the  individual  connections  should  not  be 
much  shorter  than  3  ft.  This  will  provide  for  the  differ- 
ences in  expansion  of  the  boiler  frame,  front  and  connections. 
In  some  localities  the  use  of  valves  between  a  water  column  and 
its  boiler  is  prohibited.  Such  practice  should  be  prohibited  in 
all  cases  unless  valves  are  used  which  will  give  an  unmistakable 
warning  if  they  are  closed. 

Fig.  116  (A28-2)  shows  an  ordinary,  outside-packed  plug 
cock  with  stop  screw  and  small  port  hole  through  the  plug  so 
arranged  that  steam  will  blow  to  the  atmosphere  during  the  time 
that  the  column  is  shut  off  from 
the  boiler.  The  amount  of  steam 
that  this  cock  would  blow  through 
its  port  hole  in  case  it  were  closed 
would  be  sufficient  to  give  warning, 
and  at  the  same  time  not  interfere 
with  changing  a  gage  glass,  gage 
cock  or  such  part  as  might  be  out 
of  order.  A  valve  of  this  type  will 
also  show  by  the  position  of  its  hand 
lever  whether  it  is  open  or  shut. 
If  a  gate  valve  is  used  it  should 
be  of  the  rising-stem  type,  so  that 

it  will  show  from  the  outside  whether  or  not  it  is  open.  The 
inside-screw  gate  type  such  as  is  commonly  used  for  high  pressure 
work  should  not  be  considered  in  planning  for  water  column 
connections.  The  ordinary  types  of  globe  and  angle  valves  are 
not  suitable  for  water  column  work  because  of  the  difficulty  of 
cleaning  them. 

As  shown  in  Fig.  117  (A28~3),  an  extra  heavy  cross  valve 
can  be  used  and  serve  the  purpose  as  well  as  any  of  the  usual 
methods.  The  side  plug  and  the  center  of  the  valve  may  be 
removed  when  cleaning  the  pipe  branches  to  the  water  column. 
Due  to  the  fact  that  the  stem  in  a  cross  valve  has  such  a  long 


FIG.  n6  (A28-2). 


I46 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


travel,  it  is.  easily  seen  by  the  position  of  the  hand  wheel  whether 
or  not  the  valve  is  open.  The  valve  bonnets  should  be  square 
instead  of  hexagonal  to  facilitate  removing  them  from  the  valve 
body. 

If  the  boiler  fronts  are  quite  high  the  level  of  the  water  in 
the  column  may  conveniently  be  indicated  by  a  low  down  mercury 
gage  similar  to  that  shown  in  Fig.  118  (A28-4). 

In  calculating  the  proportions  for  this  extension  device  let  the 
distance  a+b  be  13.5  in.,  when  there  will  be  0.5  Ib.  pressure  at 
the  lower  end  of  the  column.  A  column  of  mercury  about  i  in. 
high  would  balance  this  pressure.  If  the  distance  a  from  the 


FIG.  117  (A28-3). 


FIG.  118  (A28-4). 


top  of  the  water  in  the  column  to  the  upper  outlet  is  one-half 
the  height  of  the  column,  6.75  in.,  the  difference  in  pressure  at  the 
bottom  of  the  two  long  pipes  will  be  0.25  Ib.,  and  as  the  water 
stands  at  half  the  height  of  the  column  the  mercury  should  also 
stand  at  the  midpoint  of  the  glass  c.  The  proportions  are 
arranged  so  that  when  the  mercury  has  just  left  the  glass  there 
will  be  a  column  at  d  i  in.  high  balancing  the  water  column 
a-b.  If  c  has  0.75  in.  incline  in  its  length,  then  0.25  in.  length- 
wise of  tube  d  should  have  the  same  contents  as  the  entire  tube 
c.  The  water  columns  below  b  are  balanced  and  their  length 
does  not  vary  the  effect  on  the  tubes  c  and  d.  This  gage  can  be 
placed  four  or  five  feet  above  the  floor  line  and  will1  be  in  plain 
view  of  the  operator,  the  mercury  vibrating  in  the  glass  in  the 
same  manner  as  water  would  in  a  water  glass. 


LIVE  STEAM   DETAILS. 


147 


Another  method  of  showing  the  water  level  conspicuously  is  by 
the  use  of  a  lamp  in  an  enclosed  metal  casing  placed  as  shown, 
Fig.  119  (A2&-5),  the  casing  having  a  slit  in  line  with  the  glass. 
With  this  arrangement  the  water  is  well  illuminated  and  the  lamp 
is  out  of  sight,  thus  doing  away  with  the  blinding  effect  of  a  naked 
lamp  alongside  of  the  gage  glass.  The 
enclosing  case  ordinarily  is  made  of 
heavy  tin  with  the  outside  painted  and 
the  inside  left  bright  to  serve  as  a  re- 
flector. The  top  of  the  case  should 
be  left  open  for  ventilation  and  clean- 
ing. This  device  can  be  made  by  any 
tinsmith,  the  water  gage  being  standard 
with  a  close  nipple  and  coupling 
attached  between  the  glass  and  the 
column  to  set  the  glass  away  from  the 
column  a  sufficient  distance  to  ac- 
commodate the  lamp  in  its  case. 

Much  thought  and  study  have 
been  given  toward  developing  a  device 
that  will  close  the  valves  of  a  water 
column  when  the  gage  glass  breaks. 
The  principal  feature  of  nearly  all 
these  devices  is  a  check  that  falls 
away  from  its  seat  when  the  valve 
is  closed  but  is  free  to  reach  the 
seat  when  the  valve  is  open.  This  detail  is  shown  in  Fig. 

120  (A28-6). 

The  difficulty  with  this  check  for  the  gage  is  occasioned  by  the 
ball  shutting  off  the  gage  glass  after  blowing  out  through  the 
blow-off  lettered  a  in  Fig.  119  (A28-5).  The  trouble  necessary 
in  closing  and  opening  such  a  valve,  and  dropping  the  ball  off 
the  seat  is  a  strong  argument  in  deciding  against  their  use. 

Another  type  of  self-closing  water  gage   is  as  shown  in  Fig. 

121  (A28-7).      This    shut-off    device    is    not  'operated    by   the 
steam  flow  through  the  valves,  and  the  glass  may  therefore  be 
blown  out  as  violently  and  often  as  desired  without  danger  of 
closing  the  valves  to  the  boiler.     As  the  water  glass  is  practically 
the  only  means  used  for  ascertaining  the  amount  of  water  in  the 
boiler  an  operator  should  be  free  to  blow  it  out  as  often  as  neces- 


FIG.  119 


148 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


FIG.  120  (A28-6). 


sary  to  satisfy  himself  that  the  level  of  the  boiler  water  is  shown 

correctly  in  the  column.     The  gage  valves  shown  in  Fig.  121  are 

of  similar  construction  to  the  one  shown  in  Fig.  120,  but  with  the 
ball  omitted.  The  valves  have  either  a 
very  coarse  or  a  multiple  thread  on  the 
stems  and  have  levers  attached  to  the 
stems  instead  of  hand  wheels.  The  levers 
are  connected  together  and  stand  in  their 
upper  position  when  the  valves  are  open. 
A  small  wire  a  is  run  around  the  glass 
and  attached  to  the  end  of  the  lever  as 
shown.  This  wire  supports  the  weight  b 

which  will  close   the  valves  should  the  gage  glass  break.     The 

spring  c  is  to  relieve  the  valves  of  any  serious  strains  when  the 

stem  closes  on  its  seat.     The  valves  on  this  gage  can  be  closed 

at  any  time  by  detaching  the  wire  from  the 

hooked  lever.    The  small  wire  does  not  offer 

any  obstruction  to  the   view,  but  should  be 

of  sufficient  size  to  denote  the  desired  water 

level  which  is  to  be  maintained. 

Water  columns  are  often  loaded  with   too 

many  attachments   such    as    automatic   high 

and    low    alarm,    boiler    feed   regulator,   self 

gage-closing  arrangement  and  operating  chains, 

gage  cocks  with  chains,  column  valves  with 

chains,   counterweights,   etc.     Each    of    such 

devices  has  points  of   slight  merit  but  there 

is  a  danger  in  using  too  many  safety  devices. 

To  evade  the  use  of  too  many  attachments 

the  column    valves   could  be  similar  to  that 

shown  in  Fig.   120,  and  be  provided  with  a 

projecting  pin  at  the  end  of  the  lever;  water 

gages  and  gage  cocks  also  could  have  similar 

pins    arranged   for  operation    as    shown    in 

Fig.    122    (A28-8    and    9).      The    rod   with 

which   the  valves  would  be  operated  should 

have   a  long   handle  similar  to  a  window  stick.     If  the  water 

column  to  be  tended  is   16  ft.  above  the  floor,  the  rod  should 

be  about   12  ft.  long.     With  a  long  rod  the  operator  can  keep 

out  of  the  way  of  steam  and  water,  and  the  use  of  automatic 

devices  and  hanging  chains  is  done  away  with. 


FIG.  121  (A  28-7). 


LIVE   STEAM   DETAILS. 


149 


Much  trouble  is  experienced  in  keeping  gage  cocks  tight,  and 
many  stations  do  not  allow  gage  cocks  to  be  operated  except 
when  there  is  no  gage  glass  in  the  water  column.  It  is  good 
practice  to  use  two  water  gages  and  no  gage  cocks,  but  if  gage 


iy 

FIG.  122  (A 28-8,  9). 

cocks  are  to  be  used  they  should  be  of  such  form  that  they 
can  be  made  to  close  as  tightly  as  any  other  valve  and  not 
depend  on  a  small  weight,  spring  or  boiler  pressure  to  keep  them 
tight.  No  ordinary  valve  can  be  kept  tight  under  such  severe 
service. 

Fig.  122  shows  a  gage  cock  that  is  operated  by  a  pole  as  earlier 
described.     A  pressure  sufficient  to  flatten  out  the  valve  seat  is 


FIG.  123  (A  28-10). 

possible  with  this  device.  It  is  the  general  practice  in  boiler 
rooms  to  have  the  chief  fireman  of  each  shift,  as  soon  as  he  comes 
on,  open  the  gage  cocks  and  blow  out  the  columns  and  glasses 
on  all  the  boilers.  He  may  blow  out  the  glasses  again  during  his 
shift,  but  not  the  columns  nor  the  gage  cocks.  Therefore  this 
small  amount  that  gage  cocks  and  water  gage  valves  are  used 


150 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


does   not  justify  having   chains   constantly    dangling  from    the 
columns. 

There  are  numerous  makes  of  high  and  low  water  alarms  on 
the  market,  the  majority  used  being  float  operated.  On  high  pres- 
sures, say  above  140  lb.,  much  difficulty  is  experienced  with  the 
collapsing  of  floats,  and  the  screeching  of  whistles  is  also  very 
objectionable.  It  is,  however,  good  practice  to  give  warnings  with 
an  alarm  column.  Such  alarms  can  be  given  in  high  pressure 
plants  by  the  apparatus  shown  in  Fig.  123  (A28-io),  the 
essential  parts  of  which  include  the  high  and  low  electric  alarm 
column,  using  a  lamp  at  each  boiler,  a  bell  alarm  in  the  boiler  room 
and  a  " buzzer"  in  the  chief  engineer's  office. 

One  alarm  bell  will  serve  for  the  entire  plant,  and  by  having  a 
signal  lamp  at  each  column  the  particular  boiler  or  boilers  having 
high  or  low  water  will  readily  be  observed.  The  float  a  is  made 
of  aluminum  and  counter-balanced  with  the 
weight  b.  The  porcelain  insulator  c  has  pack- 
ing above  and  below  where  it  is  clamped 
"**  to  the  column  and  also  at  the  ends  where 
the  contactor  d  runs  through  the  insulator. 
The  pin  in  the  counter-weight  moves  free 
of  the  contact  segment  d  and  so  completes 
the  circuit  only  at  high  and  low  water.  The 
only  friction  that  this  device  must  over- 
come is  at  the  pins  c  and  /,  which  are  loosely 
fitted  and  made  of  brass.  There  are  no 
dripping  or  leaking  parts  to  this  column,  all 
being  sealed  and  tight.  An  open,  low- 
potential  circuit  would  be  used  with  a 
ground  return,  the  contactors  in  columns 
serving  to  ground  the  circuit. 

The  column  shown  in  Fig.  124  (A28-n) 
is  the  simplest  form  of  float  column  now 
on  the  market.  This  device  has  one  lever 
which  opens  a  whistle  valve  for  high  or 
low  water  by  pressing  either  upward  or 
downward  on  the  end  of  the  valve  stem.  The  rod  a  slides 
loosely  through  the  large  eye  in  the  end  of  the  lever.  There  are 
but  few  moving  parts,  and  as  long  as  the  float  "floats,"  satisfac- 
tory operation  and  a  loud  noise  can  be  expected  from  this  device. 


Fio.  124  (A 28-1 1.) 


LIVE   STEAM   DETAILS. 


Gage 


Class  A29  —  Live  Steam  to  Steam  Gages.  The  connection  to 
steam  gages  should  be  made  so  that  there  will  be  a  sufficient  length 
of  pipe  to  offer  condensing  surface  which  will  maintain  water  close 
to  the  gage  and  thus  care  for  any  ordinary  leak  at  a  cock,  union 
or  other  joint  near  the  gage.  For  this  and  other  reasons  gages 
are  often  placed  12  ft.  or  more  below  the  level  of  the  steam  line. 
This  arrangement  is  proper,  but  gages  so  placed  should  be  designed 
to  take  into  account  the  12  ft.  of  water  in  the  pipe,  which  would 
ordinarily  add  5  Ib.  to  the  steam  pressure.  In  other  words,  the 
pointer  should  either  be  set  back  5  Ib.  or  the  dial 
should  be  graduated  and  marked  while  there  is 
5  Ib.  more  pressure  on  the  gage  than  readings 
would  show. 

In  ordering  gages,  if  a  variation  in  readings  is 
to  be  avoided,  the  condensation  column  should 
be  given  for  each  gage.     In  ordinary  station  con- 
struction this  water  pressure  variation  is  often  as 
high   as   10  Ib.  and  leads  to  confusion  and  mis- 
understanding   of    what    the    plant    is    doing. 
Apparently  there  may  be  a  large  line  loss  between 
header  and  throttle  valve  as  shown  by  an  indica- 
tor test,  while  in  reality  the  difference  in  pressure 
is  almost  entirely  traceable  to  the  condensation 
column.     The    steam    gage    should   give   steam 
pressure   only,   not  part   steam  and   part  water  column.     This 
error  in  gages  is  often  overlooked,  with  the  result  that  several 
pressures  are  indicated  in  a  plant  and  the  gages  are  often  sup- 
posed to  be  wrong. 

The  ordinary  type  of  cock  furnished  with  the  gage  is  often 
leaky  and  a  cause  of  much  annoyance. 

The  small  needle  valve  shown  in  Fig.  125  (A2Cj-i)  has  a 
union  on  the  gage  side.  This  permits,  the  removal  of  the  gage 
without  disturbing  the  valve.  The  stuffing  box  with  this  type  of 
needle  valve  can  be  made  tight  and  kept  so,  which  is  difficult  to  do 
with  the  small  plug  cocks  often  used,  and  the  needle  valve  may 
be  had  for  a  small  additional  cost. 

Single-tube  gages  should  be  selected  for  power  plant  use, 
as  in  such  service  a  gage  is  quite  free  from  excessive  vibra- 
tion. For  locomotives  where  the  vibration  is  severe  a  single- 
tube  gage  with  its  higher  degree  of  sensitiveness  is  not  available 


FIG.  125  (As 


152  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

because  of  the  injurious  results  of  the  vibration  of  a  long  single 
tube. 

For  such  plants  as  are  built  purely  on  a  commercial  basis  and 
where  expenditures  are  not  to  be  made  for  decorative  features,  the 
iron  back  gages  with  a  nickel-plated  brass  rim  are  found  quite 
satisfactory.  Marble  gage  boards  are  now  out  of  date.  For  all 
practical  and  artistic  purposes  the  painted  plate  iron  gage  board 
has  many  advantages.  The  gages  may  be  easily  attached  to  an 
iron  board,  heat  and  water  will  not  damage  it,  and  if  it  should 
accidentally  be  damaged  the  iron  gage  board  can  be  straightened 
and  put  back  in  order.  If  its  surface  becomes  badly  marked,  an 
iron  board  can  be  repainted  by  station  help.  There  is  but  little 
chance  to  improve  the  appearance  of  an  old  or  damaged  marble 
board. 

Such  a  steel  board  is  shown  in  Fig.  126  (A2Q-2).  There 
should  be  a  slit  in  the  floor  back  of  the  board  through  which  the 
pipes  could  pass,  and  back  of  some  or  all  of  the  gages  should  be  a 
6-in.  hole  in  the  plate  to  facilitate  making  the  piping  connections. 
The  tools  can  be  supported  by  clips  attached  to  the  plate  by  small 
machine  screws.  The  board  should  have  about  6  in.  of  space 
behind  it  and  should  be  made  of  about  -^--in.  plate  with  corner 
angles  of  2  by  2-in.  angle  iron.  The  shelf  should  be  about  3  ft. 
high  and  10  in.  wide,  with  the  angle  iron  projecting  above  the  shelf. 
In  the  shelf  should  be  a  2-in.  hole  through  which  dirt  could  be 
brushed.  Round  head  rivets  with  the  heads  perfect  on  the  outside 
should  be  used.  The  board  could  be  painted  and  varnished  in 
harmony  with  the  nearby  engines.  It  would  also  be  a  good  plan 
to  make  the  top  removable  for  inspection  or  repairs  and  to  enable  a 
light  being  dropped  inside. 

The  gage  board  can  be  illuminated  in  three  different  ways:  By 
illuminated  dial  gages,  by  lamp  brackets  attached  to  the  gage 
board,  or  by  a  small  headlamp  set  back  from  the  board  and 
directed  toward  the  gages.  The  illuminated  dial  gage  brings 
into  the  design  many  details  such  as  wires  behind  the  board, 
a  lamp,  switch,  etc.,  for  each  gage,  and  a  much  more  delicate  and 
expensive  type  of  gage.  It  is  difficult  to  place  lamp  brackets 
so  as  properly  to  illuminate  the  board  and  not  obstruct  the  view 
of  the  gages.  The  use  of  a  single  small  headlight  is  by  far  the 
simplest  arrangement  to  construct,  operate  and  maintain,  and  the 
illumination  will  be  found  to  be  better  than  can  be  secured  with  side 


LIVE   STEAM   DETAILS. 


'53 


lamps  and  quite  as  good  as  with  the  illuminated  dial  gages.  If  the 
gage  board  is  placed  at  the  wall  between  the  high  and  low  pressure 
cylinders  of  one  of  the  engines,  then  the  small  headlamp  can  be 
mounted  on  a  generator  sufficiently  high  so  that  its  light  will 
not  cast  the  shadow  of  the  operator  on  the  board  in  front  of  him. 
The  boiler  steam  gages  should  be  placed  as  low  as  possible,  and 
care  should  be  taken  that  they  are  graduated  for  the  known 
column  of  condensation. 

In  Fig.  127  (A2Q-3)  is  shown  a  steel  gage  board  placed 
above  the  floor  with  a  cover  channel  over  the  pipes  and  wire 
conduit  leading  to  it.  The  anchors  for  holding  the  board  to  the 
wall  should  be  of  o-5-in.  wrought  iron  with  polished  or  nickel- 
plated  nuts.  The  rims  of  the  gages  and  possibly  the  name 


FIG.  126  (A29-2). 


FIG.  127  (A29~3). 


plate  and  valves  would  look  well  if  nickel  plated.  The  lamp 
brackets  and  rosettes  should  also  be  plated.  The  board,  channel 
and  cases  of  the  gages  should  be  painted  and  varnished  the  same 
as  nearby  machinery.  The  exposed  rivet  heads  should  be  care- 
fully preserved  while  heading  the  rivets  at  the  back  of  the  gage 
board.  Such  a  gage  board  as  this  can  be  made  at  small  cost  and 
will  be  found  very  serviceable  and  attractive,  in  fact  even  more 
attractive  than  the  nearby  stairways,  trusses,  building  columns  and 
structural  work.  When  erecting  the  station  the  structural  steel 
contractor  could  be  asked  to  furnish  the  board  and  channel,  and 
the  steam  fitter  could  erect  the  board  and  connect  the  piping.  The 


154  STEAM   POWER  PLANT  PIPING   SYSTEMS. 

painting  should  be  done  by  the  same  contractor  who  paints  the 
machinery. 

Class  A30  —  Live  Steam  from  Safety  Valves  through  Roof.     In 

piping  safety  valves,  the  most  satisfactory  method  is  to  run  the 
pipe  for  each  valve  through  the  roof.  When  there  are  a  large 
number  of  boilers  each  having  two  valves,  this  will  require  con- 
siderable cutting  of  the  roof,  but  as  a  rule  it  is  cheaper  to  run 
each  pipe  to  the  atmosphere.  The  increased  expense  would  in  all 
probability  be  justified,  because  with  the  separate  pipes  the  operator 
can,  by  going  up  on  the  roof,  readily  tell  which  valve  blows  first, 
which  is  leaking,  the  amount  of  leak,  etc.  If,  on  the1  other  hand, 
the  pipes  are  tied  together  in  one  main,  it  becomes  difficult  to  deter- 
mine which  valve  is  blowing  or  leaking.  Many  plants  use  a 
short  stub  and  allow  the  steam  to  escape  into  the  boiler  room 
whenever  the  valves  blow  off.  This  is  wrong,  as  the  firemen  have 
enough  hardships  without  having  any  more  put  upon  them  under 
the  plea  that  if  they  look  after  the  pressure  it  will  not  blow. 
There  are  times  when  the  pressure  can  be  controlled,  but  more 
often  this  is  not  the  case.  By  allowing  the  steam  to  escape  into 
the  boiler  room  the  operator  will  lose  money,  for  no  one  will  stay 
in  the  room  full  of  steam  if  he  can,  by  any  excuse,  get  out,  and  if  he 
does  stay,  he  will  do  nothing  until  the  disturbance  ceases. 

In  most  cases  one  valve  will  open  before  the  others  and  may 
continue  to  blow  by  itself  for  5  min.  This  may  be  one  of 
two  valves  on  a  25o-h.p.  boiler,  discharging  say  10  per  cent  of  the 
output  of  the  boiler.  The  boiler  might  possibly  be  using  1,000  Ib. 
of  coal  per  hour,  hence  a  10  per  cent  blow-off  would  waste  100  Ib. 
of  fuel  or  a  loss  of  10  cents  per  hour  for  coal.  If  for  any  reason 
three  employes  leave  the  room  during  the  blow-off  period,  the 
employer  will  lose  at  the  rate  of  not  less  than  60  cents  per  hour. 
Thus  if  he  desires  that  the  inside  blow*-off  arrangement  be  profitable 
he  must  reduce  the  number  of  blow-offs  to  less  than  one-sixth  of 
what  it  would  be  if  piped  through  the  roof.  This  is  impossible. 
Fig.  128  (A3o-i)  shows  an  independent  pipe  from  the  safety 
valve  passing  up  through  the  roof.  Where  there  are  a  number  of 
such  pipes  the  use  of  cast  iron  roof  collars  is  justified.  These  col- 
lars should  be  about  three-eighths  inch  thick,  with  the  exception 
of  the  threaded  hub  of  the  umbrella,  which  should  be  about  five- 
eighths  inch  thick.  The  upper  portion  of  the  umbrella  is  used  as 
a  coupling  for  the  two  lengths  of  pipe,  permitting  upper  portion 


LIVE  STEAM  DETAILS. 


155 


of  pipe  to  be  cut  at  the  shop.  The  lower  section,  or  roof 
sleeve,  should  be  provided  with  several  projections  which  will 
just  allow  the  sleeve  to  slip  over  the  pipe  and  at  the  same  time 
steady  it.  This  roof  sleeve  should 
be  set  after  the  pipes  are  in  position. 
The  roofing  felts  should  be  cleared 
of  gravel  and  coated  with  a  hot 
cement  in  which  the  sleeve  should  be 
firmly  bedded  and  tightly  bolted 
through  the  roof  boards.  The  joints 
and  the  tops  of  the  flanges  should 
also  be  well  coated  with  this  cement. 
The  sleeve  should  not  be  less  than 
4  in.  in  height,  and  there  should  be 
at  least  one-half  inch  clearance  between 
the  sleeve  and  the  umbrella.  Galva- 
nized sheet  iron  is  generally  used  in 
this  work,  but  this  is  frail  and  easily 
damaged.  Whenever  the  safety  valves 
are  taken  off  for  repair,  the  light 
galvanized  iron  work  usually  becomes 
so  badly  injured  that  it  is  unfit  for 
further  use.  If  the  sleeve  and 
umbrella  be  made  of  cast  iron  they 
furthermore  will  be  inexpensive. 

Attention  should  be  given  to  the  safety  valve  drain.  This  open- 
ing should  be  free  to  the  atmosphere  at  all  times,  as  much  damage 
results  if  water  or  condensation  is  allowed  to  remain  in  the  valve 
and  cause  water  hammer  when  the  steam  is  escaping.  A  rule 
should  be  observed  that  only  the  discharge  from  safety  valves  on 
boilers  that  are  commonly  shut  down  at  the  same  time  should  be 
tied  into  a  common  pipe  line.  It  is  quite  imperative  that  this  rule 
be  observed,  as  boiler  insurance  companies  will  not  allow  gate 
valves  in  safety  valve  branches,  and  without  gate  valves  in  the 
safety  valve  branch  connected  to  more  than  one  working  boiler, 
the  operator  would  be  liable  to  serious  injury  when  making  repairs. 
If  but  one  boiler  at  a  time  is  shut  down  for  cleaning,  then  but  the 
two  or  three  valves  on  that  boiler  should  be  tied  into  the  one  line  to 
the  atmosphere.  If  the  plant  has  a  number  of  boilers  which  are 
shut  down  in  batteries  of  two,  then  the  safety  valves  on  these  boilers 


FIG.  128  (Aso-i). 
will   stand   abuse   and 


1 56 


STEAM  POWER  Pi.rl.vr  PtPL\'C  SYSTEMS. 


may  be  discharged  into  a  common  main.  In  most  cases  it  is  better 
to  tie  in  only  the  discharge  pipes  from  the  one  boiler,  and  if  the  roof 
is  not  over  20  ft.  above  the  safety  valve,  it  will  be  found  less  expen- 
sive to  run  separate  pipes.  The  tie  should  be  made  far  enough 
away  from  the  safety  valve  to  allow  for  expansion,  and  the  side 

outlet  foot  tee  should  be  provided  with 
a  drain  as  shown  in  Fig.  129  (A3O-2). 
The  foot  tee  should  have  a  substantial 
support  to  enable  it  to  carry  the  weight 
of  the  standpipe  and  its  branches  so 
that  a  valve  can  be  removed  without 
causing  any  severe  strain. 

The  arrangement  shown  in  full  line 
in  Fig.  130  (A30-3)  is  not  considered 
good  practice.  The  safety  valves 
should  not  be  taken  off  of  any  boiler 
steam  branch  or  from  that  portion 
of  the  boiler  where  steam  is  on  its 
way  to  the  pipe  main.  They  should 
be  placed  where  there  is  the  largest 
volume  of  steam.  The  steam  flowing 
through  the  pipe  line  does  not  flow 
with  a  uniform  velocity.  The  varia- 
tion in  pressure  at  the  boiler  connection  may  be  as  much 
as  five  pounds  when  steam  is  being  delivered  to  a  large  low- 
speed  engine.  This  fluctuation  of  pressure  exists  in  all  the 
steam  lines  as  well  as  in  the  boiler,  but  since  there  is  such  a  large 
steam  volume  in  the  boiler,  the  pressure  there  is  not  noticeably 
affected.  In  the  pipe  line  this  variation  is  very  perceptible,  and  its 
amount  may  be  determined  by  placing  an  engine  indicator  on  the 
lines  and  moving  the  drum  slowly,  allowing  the  pulsations  to  indi- 
cate a  diagram  which  will  resemble  the  teeth  of  a  saw.  When  the 
safety  valves  are  subjected  to  this  pulsating  pressure  they  will 
chatter  if  the  pressure  is  close  to  the  blow-off  point.  If  the  safety 
valves  are  set  for  a  drop  in  pressure  of  3  lb.,  the  pulsating  pressure 
due  to  the  engine  cut-off  is  sufficient  to  run  the  pressure  up  to  the 
blow-off  point,  after  which  it  drops  almost  instantly  to  the  closing 
point,  so  that  by  synchronous  pulsation  with  the  engine  the  valve 
will  make  from  150  to  200  beats  per  minute  or  twice  for  each 
engine  revolution.  One  minute's  wear  occasioned  by  this  beating 


FIG.  129  (A30-2). 


LIVE   STEAM   DETAILS. 


157 


is  equal,  possibly,  to  a  month's  wear  due  to  ordinary  service.  To 
secure  the  proper  wear  the  safety  valves  should  be  separated  from 
the  steam  connection  as  shown  by  the  dotted  lines  in  Fig.  130 
(A3°-3)-  This  may  be. done  if  provision  is  made  when  the  boiler 
contract  is  let. 


FIG.  130  (A3o-3). 

Class  A31  —  Live  Steam  for  Heating  Purposes.  Steam  con- 
nections to  heat  water  for  the  lavatory  should  be  avoided  whenever 
possible,  as  numerous  difficulties  are  thereby  occasioned.  A  coil 
can  be  attached  to  a  blind  flange  at  the  end  of  a  header  through 
which  the  water  to  be  warmed  may  pass  as  is  shown  in  Fig.  131 
(A3i-i).  In  order  to  avoid  generating  steam  when  but  little  water 
is  being  used,  the  water  should  pass  to  the  coil  at  boiler  pressure. 
After  leaving  the  coil,  the  water  should  pass  through  a  pressure 
reducing  and  a  relief  valve  before  reaching  the  plumbing  fixtures. 
When  high  pressure  and  high  temperature  water  is  reduced  in 
pressure  by  passage  through  a  reducing  valve,  it  will  partially 
evaporate  in  the  low-pressure  line,  thus  causing  water  hammer  and 
very  unsatisfactory  water  service. 

A  very  satisfactory  method  for  heating  low-pressure  water  with 
steam  of  a  higher  pressure  is  shown  in  Fig.  132  (A3 1-2).  The 
heating  coil  a  takes  steam  through  the  valve  b,  which  is  con- 


I58 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


trolled  by  means  of  the  thermostat  tube  c.  The  thermometer  d 
shows  the  temperature  of  the  water,  which  can  be  altered  by 
changing  the  set  of  the  valve  stem  at  the  sleeve  e.  This  sleeve  is 

similar  to.  a  turn-buckle,  having 
lock  nuts  as  shown.  The  post  / 
is  made  of  a  solid  bar  which 
assists  in  holding  the  valve  secure- 
ly and  prevents  springing.  Water 
is  fed  in  at  g  and  passes  out  at  h. 
The  lower  end  of  the  coil  is  open, 
which  allows  the  steam  drips  to 
FIG.  131  (A3i-i).  discharge  into  the  warm-water 

receiver  j.     In  case  an  unusually 

large  temporary  demand  is  made  on  the  heater,  the  steam  will  flow 
through  the  coil  and  into  the  water  direct.  In  regular  operation 
the  coil  should  be  partly  filled  with  water. 


FIG.  132  (A3i-2).  FIG.  133  (A32-i). 

Class  A32  —  Live  Steam  to  prevent  Freezing  of  Roof  Conductors. 

Wherever  possible,  the  conductors  should  be  so  arranged  that  they 
will  not  be  exposed  to  lower  temperatures  than  that  of  the  roof. 
If  it  is  necessary  to  locate  conductors  outside  of  the  building  this 


LIVE  STEAM  DETAILS.  159 

cannot  be  effected,  and  the  only  thing  to  do  is  to  supply  the  conduc- 
tors with  either  exhaust  or  live  steam.  If  the  plant  is  operated 
condensing,  it  is  quite  probable  that  all  the  exhaust  steam  from  the 
auxiliaries  will  be  condensed  in  the  heater.  The  openings  into 
conductors  should  be  quite  small.  For  this  purpose  about  a  three- 
eighths  inch  pipe  with  the  valve  inside  the  wall  should  be  used  and 
it  should  be  drained  into  the  conductor  as  shown  in  Fig.  133 
(A32-i).  The  lower  section  a  should  be  of  cast  iron.  The  upper 
portion  of  the  conductor  may  be  made  of  galvanized  iron  and  the 
sewer  of  tile.  The  small  pipe  should  pass  through  a  i.5-in.  pipe 
sleeve  built  in  the  wall.  This  is  a  somewhat  extravagant  use  of 
steam,  but  it  is  less  expensive  than  the  frequent  renewing  of  con- 
ductors. In  general  the  roofs  of  power  stations  are  quite  flat  and 
are  not  exposed  to  any  extent  to  the  wind.  For  this  reason  they 
are  usually  very  warm  even  in  the  coldest  weather,  but  conductors 
placed  on  the  outside  of  buildings  will  usually  freeze  unless  heat 
be  admitted  to  them.  Some  saving  may  be  effected  by  the  use  of 
high  temperature  drains.  A  system  that  will  discharge  vapors 
into  sewers  so  that  the  vapors  will  pass  through  the  conductors 
will  usually  cause  as  much  damage  by  rusting  out  the  conductors 
as  would  be  occasioned  by  freezing.  The  best  arrangement  that 
can  be  made  with  outside  conductors  is  to  use  live  steam  only 
when  needed. 

Class  A33  —  Live  Steam  to  Low-pressure  Cylinder.  In  many 
cases  a  live  steam  connection  to  the  low-pressure  cylinders  is 
furnished  by  the  engine  builder.  This  connection  may  be  either 
a  warming  pipe  or  a  steam  line  to  the  low-pressure  side  to  be 
used  when  the  low-pressure  side  is  run  independent  of  the  high- 
pressure  side.  There  are  cases  where  it  is  good  policy  to  arrange 
a  cross-compound  engine  so  that  the  low-pressure  side  can  be 
run  without  the  high-pressure  side.  Ordinarily  this  detail  is 
found  necessary  when  the  plant  has  been  arranged  with  but  one 
or  two  large  engines.  In  such  cases  there  is  no  reserve  provided, 
and  in  order  to  enable  the  plant  to  operate  it  is  necessary  to  use 
the  half  of  the  engine  that  is  in  order.  There  are  also  certain 
instances  where  it  is  good  practice  to  lay  out  a  plant  with  but 
one  or  two  engines.  This  would  be  the  case  when  the  original 
installation  is  to  be  increased  within  a  short  time  by  the  addition 
of  engines  of  the  same  size,  as  by  this  means  the  use  of  small  and 
large  engines  in  the  same  plant  is  avoided. 


i6o 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


A  suitable  arrangement  of  piping  is  shown  in  Fig.  134 
(A33~i)  whereby  the  high-pressure  side  can  be  exhausted  to  the 
condenser  or  to  the  atmosphere,  or  the  low-pressure  side  can 
take  steam  through  the  reducing  valve  a  and  be  protected  by 
the  relief  valve  b,  set  at  about  25  Ib.  The  small  valve  c  is 
the  by-pass  for  warming  up  the  low-pressure  side.  The  valve  d, 


FIG.  134  (A33-i). 

which  shuts  off  the  condenser,  should  be  motor  operated  if  it  is 
larger  than  20  in.  The  atmospheric  valve  is  shown  at  e  and  the 
main  steam  throttle  at  /.  The  horizontal  valves  are  used  only 
when  changing  over  these  connections  and  should  not  be  fitted 
with  operating  stands  on  the  engine-room  floor  as  they  are  not 
used  often  enough  to  warrant  the  additional  expense  or  the  extra 
floor  space  which  they  take  up.  The  high-pressure  throttle  /, 
the  low-pressure  throttle  g,  the  by-pass  c,  and  the  electric  buttons 
for  the  valve  d,  are  the  only  operating  devices  which  are  necessary 
on  the  engine-room  floor. 


LIVE   STEAM   DETAILS.  l6l 

This  system  of  piping  to  both  the  high  and  low-pressure 
cylinders  is  frequently  carried  to  an  extreme.  In  stations  having 
three  or  more  units  it  is  useless  to  complicate  the  piping  with  the 
extra  parts  required.  If  an  engine  is  out  of  order  the  operator 
will  invariably  shut  down  the  entire  unit,  notwithstanding  the 
fact  that  it  may  be  piped  to  run  on  either  side.  There  are  many 
plants  piped  in  this  manner  that  have  never  made  use  of  the 
arrangement,  and  there  are  cases  where  it  would  seem  that  they 
would  certainly  find  it  to  their  advantage  to  use  this  piping 
system  rather  than  shut  down  the  entire  unit.  For  stations 
having  a  large  number  of  units  it  is  the  better  practice  to  pro- 
vide the  simplest  possible  arrangement  that  will  insure  the  best 


FIG.  135  (A33-a). 

protection  of  the  entire  unit  as  a  whole.  Straight  connections 
from  one  opening  to  another  should  be  avoided,  as  continuous 
trouble  with  the  joints  is  almost  certain  to  result. 

Fig-  135  (A33-2)  illustrates  the  "straight-line  connection" 
which  is  used  by  a  number  of  engine  builders.  This  connection 
is  difficult  to  make  and  so  little  provision  is  allowed  for  expan- 
sion that  severe  strains  are  placed  on  the  joints  under  the  cylin- 
ders. Such  strains  should  be  relieved  as  much  as  possible  in 
order  to  avoid  the  necessity  of  frequent  renewal.  These  joints 
are  so  situated  that  it  is  quite  difficult  to  make  a  connection  that 
will  stand  ordinary  strains  and  therefore  when  subjected  to  the 
strains  of  the  piping  as  shown  in  Fig.  135  ^33-2)  a  great 
deal  of  trouble  will  result. 

The  use  of  a  warming  pipe  for  low-pressure  cylinders  is  not 
universal  with  corliss  engine  installations.  It  is  possible  to  send 
steam  through  the  high-pressure  cylinders  to  the  receiver  without 
the  use  of  a  separate  warming  pipe.  Before  the  engine  is  started 
steam  should  be  blown  through  the  steam  valves  in  and  out  of 
the  cylinder  and  through  the  exhaust  valves  on  both  sides  of 


162  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

the  piston.  This  is  possible  with  any  engine  having  a  release 
connection  at  the  end  of  the  valve  rods  and  a  lever  for  rolling  the 
valves  by  hand.  When  a  warming  pipe  is  used  the  steam  is  dis- 
charged into  the  intermediate  receiver  or  one  of  the  pipe  connec- 
tions through  a  small  pipe,  say  a  2-in.  pipe  for  a  2,ooo-hp.  engine, 
with  the  valve  stem  run  through  the  floor  and  fitted  with  a  stand. 
If  the  valve  gear  is  not  provided  with  a  releasing  device,  it  is  advis- 
able to  run  a  warming  line  to  the  intermediate  connection  between 
the  high  and  low-pressure  sides,  so  that  the  low-pressure  side 
will  have  steam  when  the  engine  starts  to  roll  over.  In  case 
steam  is  taken  from  the  header  above  the  engine  having  a  branch 
to  the  throttle  over  the  high-pressure  cylinder,  the  low-pressure 
live  steam  connection  should  be  a  separate  branch  from  the 
header.  This  will  simplify  the  piping  arrangement. 

Class  A34  —  Live  Steam  to  Engine  Cylinder  Jackets.  Steam 
connections  to  engine  cylinder  jackets  are  not  ordinarily  required, 
the  general  practice  being  to  furnish  the  engines  without  jackets. 
Where  the  jackets  are  furnished,  the  steam  to  and  the  drips  from 
the  jackets  are  under  full  boiler  pressure  and  the  drips  are 
returned  to  the  boiler  through  a  return  system  similar  to  that 
used  for  the  other  drips  in  the  plant.  In  order  to  discharge  these 
drips  together  with  other  drips  of  boiler  pressure  the  jackets  used 
must  be  of  ample  size  to  avoid  any  perceptible  pressure  loss  due 
to  the  small  size  of  the  pipe  connections. 

Class  A35  —  Live  Steam  to  Live  Steam  Purifier.  There  is  but 
one  important  requisite  in  the  steam  connection  to  the  live  steam 
purifier  which  is  to  deliver  steam  to  the  purifier  at  a  pressure 
sufficient  to  permit  water  to  flow  by  gravity  to  the  boilers.  If  the 
purifier  is  mounted  at  a  sufficient  height  above  the  boilers  to 
allow  a  loss  in  steam  pressure  before  delivery  to  the  purifier,  the 
steam  branch  may  be  run  from  the  header.  A  good  method  of 
piping  when  the  purifier  is  placed  but  a  few  feet  above  the  boilers 
is  shown  in  Fig.  136  (A35-i).  If  three  or  four  boilers  are 
supplied  by  the  purifier,  the  branches  can  be  run  into  a  main 
which  has  a  single  connection  to  the  purifier  or  the  three  or  four 
branches  may  be  separately  run  to  the  purifier  with  a  valve  in 
each  branch.  The  water  column  a  indicates  the  head  at  which 
water  is  to  be  delivered  to  the  boiler.  This  head  must  be  greater 
than  the  combined  losses  of  the  steam  flowing  through  its 
branches  to  the  purifier,  the  loss  in  the  head  of  the  water  flowing 


LIVE   STEAM   DETAILS. 


I63 


from  the  purifier  to  the  boiler,  the  loss  in  the  head  of  the  water 
passing  through  the  check  valve,  and  the  loss  in  the  head  in  the 
main  steam  header  as  measured  at  the  different  boiler  branches. 
These  losses  could  scarcely  be  measured  on  a  gage  reading  to  165 
Ib.  of  steam,  but  when  considered  in  connection  with  the  head  a, 
that  pressure  may  be  sufficient  to  prevent  a  flow  to  the  boiler. 
When  a  is  4  to  6  ft.  there  can  be  but  very  slight  losses.  In 


FIG.  136  (A35-i). 

fact  the  combined  losses  previously  mentioned  would  be  less 
than  3  Ib.  per  square  inch.  These  losses  should  be  calcu- 
lated for  not  less  than  three  times  as  much  water  and  steam 
flowing  as  the  boiler  rating  would  indicate,  in  order  to  permit 
bringing  the  water  up  to  its  proper  line  while  the  boiler  is  being 
crowded. 

Class  A36  —  Live  Steam  to  Other  Buildings.  An  inexpensive 
and  satisfactory  method  of  running  supply  lines  to  other  build- 
ings for  driving  machinery,  heating,  etc.,  is  shown  in  Fig.  137 


1 64 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


(A36-i).  The  piping  is  run  through  tile  and  if  a  straight  run 
cannot  be  made  from  the  one  building  to  the  other,  a  well  is  placed 
at  the  intersection  to  enable  a  line  that  is  out  of  order  to  be  discon- 
nected. The  lines  should  be  located  so  that  they  can  be  drawn 
back  into  the  room  at  least  the  length  of  the  pipe,  enabling  the 
removal  of  the  entire  line  without  disturbing  the  ground.  If  the 
building  a  will  not  permit  drawing  the  pipe  into  it,  the  line  from 


FIG.  137  (A36-i). 

the  building  a  to  the  building  b  may  be  drawn  through  into  the 
building  b.  The  steam  separators  c  and  d  are  so  placed  that  they 
will  take  care  of  the  condensation.  The  pipes  in  the  tile  should  be 
left  bare  and  the  air  space  closed  by  a  manhole  cover  with  the  end 
openings  at  the  walls  plugged  with  asbestos.  The  tile  should  be 
cemented  at  the  joints  and,  if  convenient,  the  well  should  have  a 


LIVE   STEAM   DETAILS. 


I65 


drain  to  the  sewer.     What  little  moisture  would  work  into  the  tile 
or  well  would  be  quickly  evaporated. 

Class  A37  —  Live  Steam  Branch  to  the  Heater  Coil  in  the  Engine 
Receiver.  This  steam  connection  belongs  to  that  class  of  small 
station  piping  details  which  secure  economy  only  by  complicating 
the  general  system  of  operation.  It  is  generally  known  that 
reheating  the  exhaust  after  it  leaves  the  high-pressure  cylinder 
greatly  improves  the  lubricating  conditions  in  the  low-pressure 
cylinder,  but  little  other  benefit  is  thus  secured.  To  avoid  an 
actual  loss  of  heat  it  is  necessary  to  return  the  drips  from  the 
reheater  to  the  boiler  in  such  a  manner  that  the  heat  units  in  this 


J            L 

"i  ,  ,  r 

J  L|— 

,  HL^ 

I 

1  !  !  T^ 

]^/^/^^ 

fli  I    1             -  -1  —  l-dl      **a 

70 


'S////////////////////////////////// 

FIG.  138  (As 7-1) 


high-temperature  water  are  retained.  An  efficient  method  of 
accomplishing  this  is  to  pipe  the  return  drips  to  the  boilers  inde- 
pendent of  the  regular  feed  main. 

In  Fig.  138  (A3 7-1)  is  shown  the  usual  arrangement  for  connect- 
ing a  receiver  between  the  high  and  low-pressure  cylinders.  The 
live  steam  passes  to  the  reheater  coil  through  the  connection  a. 
The  drips  pass  through  the  pipe  b,  and  are  received  by  the  pump  c. 
This  pump  allows  the  pressure  in  the  pipe  b  to  be  less  than  that 
in  the  steam  pipe  a.  The  steam  branch  a  may  be  taken  from  the 
engine  branch  or  from  the  upper  portion  of  the  main  header,  but  a 
better  method  is  to  take  the  steam  from  the  drip  opening  of  the 


1 66  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

steam  separator  or  from  a  drip  pocket  in  the  main  header.  These 
drain  details  will  be  taken  up  more  fully  under  the  subject  of 
"Drips." 

Class  A38  —  Live  Steam  Branches  to  and  from  Superheaters. 
The  superheater  when  placed  in  a  boiler  setting  becomes  a  part  of 
the  boiler  and  no  provision  should  be  made  for  a  by-pass  around  it, 
since  its  location  in  the  furnace  is  such  that  unless  steam  is  flowing 
through  the  superheater  it  will  soon  be  damaged. 

The  principal  difference  in  pipe  lines  for  superheated  and  satu- 
rated steam  is  the  reduced  size  of  the  former.  This  reduction  is 
favored  by  the  manufacturers  of  superheaters  since  they  have  proven 
by  demonstration  that  it  is  more  economical  to  increase  friction 
losses  and  reduce  the  loss  by  radiation  than  it  is  to  increase  the  loss 
by  radiation  and  decrease  the  friction  losses.  This  radiation  loss 
may  also  be  reduced  in  the  use  of  saturated  steam. 

The  subject  of  radiation  from  extremely  large  pipes,  receivers, 
etc.,  is  not  sufficiently  considered  in  connection  with  the  use  of  satu- 
rated steam.  The  boiler  manufacturer  will  guarantee  a  certain 
quantity  and  quality  of  steam  as  it  leaves  the  boiler  and  the  engine 
manufacturer  will  guarantee  to  perform  a  specified  amount  of  work 
with  a  certain  quantity  and  quality  of  steam  delivered  at  the 
throttle.  Until  the  superheater  manufacturer  came  into  the 
market,  no  one  had  interested  himself  sufficiently  to  guarantee  a 
minimum  loss  between  the  boiler  and  the  engine.  The  manu- 
facturer of  the  superheater  has  to  assume  this  loss  in  connection 
with  his  apparatus  since  the  success  of  his  business  virtually 
depends  upon  reducing  this  loss  to  a  minimum  and  in  seeing  that 
the  superheater  receives  the  credit  for  the  saving. 

The  use  of  small  radiating  surfaces  for  superheated  steam  is 
essential  on  account  of  the  high  temperature  and  rapid  radiation. 
The  entire  volume  of  superheated  steam  in  a  pipe  is  not  all  of  the 
same  degree  of  temperature,  and  this  point  should  not  be  over- 
looked in  making  piping  arrangements  for  superheated  steam. 
This  fact  is  well  understood  by  manufacturers  of  superheaters,  and 
to  insure  a  uniform  amount  of  superheat  a  number  of  methods  are 
resorted  to  for  bringing  all  or  as  much  of  the  steam  as  possible  to 
the  heating  surface. 

One  method  of  doing  this,  by  removing  the  "core"  in  a  super- 
heater tube,  is  shown  in  Fig.  139  (A38-i).  The  steam  in  the 
space  a  is  out  of  the  circulation  of  the  flowing  steam,  being  con- 


LIVE   STEAM   DETAILS.  1 6"; 

fined  inside  the  tube  c.  The  steam  in  space  b  is  that  which  is 
flowing  and  taking  up  the  heat  delivered  by  the  outer  tube  d.  If 
the  tube  c  were  not  placed  in  the  position  shown,  the  steam  would 
travel  through  the  space  a,  and,  due  to  the  frictional  resistance  of 
the  tube  d,  the  steam  next  to  this  tube  would  move  slower  than 
that  at  the  center.  Since  this  steam  at  the  center  will  take  up 
superheat  slowly,  it  will  cause  the  tube  d  to  be  raised  to  a  very 
high  temperature  and  thus  reduce  its  conductivity  and  capacity. 

When  passing  through  supply  lines  the  superheated  steam  flows 
through  the  center  of  the  pipe.  The  steam  lying  next  to  the  pipe 
is  deprived  of  its  superheat  and  condenses.  The  amount  of  steam 
that  will  be  thus  condensed  is  determined  by  the 
radiating  surface  of  all  the  lines  between  the  boiler 
and  the  machine  using  the  steam.  If  the  lines 
throughout  their  entire  length  are  small,  very  short, 
and  the  steam  flows  through  them  at  a  rate  of 
10,000  ft.  per  minute,  little  or  no  condensation  FIG.  139  (A38-i). 
will  take  place,  and  the  losses  by  radiation 
will  be  shown  by  the  loss  of  superheat.  Large  headers,  steam 
receivers,  etc.,  should  be  avoided  when  superheated  steam  is  used. 
Condensation  may  not  show  in  the  lines  while  running,  but  it  is 
necessary  to  provide  as  ample  means  for  removing  the  condensa- 
tion as  would  be  used  in  piping  for  saturated  steam.  Large  drip 
pockets,  etc.,  should  be  avoided,  and  in  every  detail  radiation 
should  be  reduced  to  the  least  possible  amount.  It  may  be  possible 
to  locate  the  steam  main  and  its  branches  in  a  portion  of  the  build- 
ing where  air  can  be  confined  and  the  radiation  losses  reduced. 
The  principal  advantage  to  be  gained  by  the  use  of  superheated 
steam  is  the  saving  in  condensation  losses. 

Whatever  precautions  are  taken  toward  reducing  the  condensa- 
tion losses  between  the  boilers  and  the  steam  driven  machines  are 
savings,  whether  the  steam  used  be  saturated  or  superheated.  A 
slight  pressure  drop  in  the  use  of  superheated  steam  may  be 
allowed  in  order  to  save  heat  units,  but  the  maintenance  of  the  boiler 
pressure  as  far  as  the  engine  throttle  when  using  saturated  steam 
is  open  to  argument. 

There  is  a  certain  size  of  line  which  will  give  the  least  total  loss 
for  every  requirement.  With  a  given  line  a  slight  saving  in  the  one 
class  of  loss  is  accompanied  by  a  correspondingly  greater  loss  in  the 
other  class.  The  tendency  seems  to  be  toward  the  use  of  large 


1 68  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

headers  and  pipes,  thus  increasing  the  heat  unit  losses.  In  many 
situations  the  present  pipe  lines  could  be  considerably  reduced  in 
size  and  if  carefully  planned  would  not  cause  any  increase  in 
the  pressure  drop  from  the  boiler  to  the  steam-driven  machine. 
Fig.  140  (A38-2)  shows  a  system  of  piping  suitable  for  super- 
heated steam.  The  header  is  small  and  more  in  the  nature  of  an 
equalizer  or  emergency  line,  being  possibly  the  size  of  the  engine 


FIG.  140  ( 


connection.  For  regular  service  the  steam  would  pass  from  the 
boiler  directly  to  the  engine  without  any  abrupt  turns.  The 
small  amount  of  steam  passing  through  the  header  from  one  unit 
to  another  would  bring  about  the  only  noticeable  heat  loss.  If  it  is 
found  to  be  desirable  the  header  may  be  shut  off  and  each  unit 
used  separately. 

Class  A39  —  Live  Steam  Branch  to  Turbines.  The  general 
design  of  steam  branches  to  turbines  should  be  much  the  same 
as  those  for  engines,  embodying  in  addition  the  special  features 
pertaining  to  superheated  steam.  One  special  feature  in  regard 
to  these  connections  is  the  size  of  pipe  required.  An  engine 
which  cuts  off  at  one-quarter  of  its  stroke  and  has  a  pipe  branch 
in  which  the  ultimate  steam  velocity  does  not  exceed  10,000  ft.  per 
minute  would  require  a  branch  which  would  have  four  times  the 
cross-sectional  area  of  the  turbine  branch  in  which  the  steam  is 
flowing  continously.  A  reciprocating  engine  not  only  requires  a 
full  amount  of  steam  at  short  periods  but  also  makes  necessary  the 
alternate  acceleration  and  retardation  of  the  volume  of  steam  flow- 
ing through  the  steam  connection.  The  pressure  in  a  large  steam 
main  will  show  a  very  perceptible  change  on  account  of  the  cut-off 
of  the  engine,  this  change  being  caused  both  by  the  sudden  with- 
drawal of  the  steam  to  the  engine  and  its  consequent  expansion, 
and  also  on  account  of  the  inertia  of  the  steam  at  the  high  velocity 


LIVE  STEAM   DETAILS.  169 

being  suddenly  brought  to  a  stop.  Steam  turbines  relieve  the  pipe 
systems  of  these  steam  vibrations.  Such  vibrations  as  may  be 
caused  by  the  turbines  in  taking  steam  are  not  productive  of  pipe 
vibrations  on  account  of  the  short  period  of  the  vibrations  and  the 
inability  of  the  heavy  masses  to  pulsate  in  synchronism  with 
them. 


CHAPTER    XI. 
VACUUM    EXHAUST    PIPING. 

Class  Bl  and  2  —  Vacuum  Exhaust  Piping  Main  and  Branch  to 
Engines.  The  vacuum  lines  are  in  most  cases  the  largest  pipe 
lines  in  the  plant,  and  special  care  should  be  taken  in  their  design 
in  order  to  reduce  the  loss  of  head  in  the  flow  through  them.  The 
loss  of  but  one-half  a  pound  in  the  pipe  line  means  i  in.  less 
vacuum  at  the  engine  than  at  the  condenser.  •  A  loss  that  would 
scarcely  be  measurable  in  a  steam  line  would  be  too  great  to  be 
allowed  in  a  vacuum  line.  Ordinarily,  with  26  in.  of  vacuum, 
there  would  be  70  cu.  ft.  of  steam  passing  through  the  vacuum  line 
for  each  cubic  foot  passing  through  the  live  steam  line,  and  10  cu.  ft. 
of  atmospheric  exhaust  to  i  cu.  ft.  of  live  steam.  An  engine 
having  a  i2-in.  steam  line  will  ordinarily  have  a  24-in.  exhaust. 
Assuming  that  the  continuous  flow  of  a  6-in.  line  is  equivalent 
to  the  flow  of  a  12-in.  line  when  steam  is  cut  off  at  one-quarter  of 
the  stroke  or  in  one-quarter  of  the  time,  there  is  a  diametrical  ratio 
between  the  24-in.  exhaust  and  the  6-in.  steam  main  of  4  to  i  and 
an  area  ratio  of  16  to  i.  The  volume  of  vacuum  exhaust  being 
seventy  times  that  of  steam,  it  is  then  true  that  steam  in  vacuum 
lines  must  have  a  velocity  about  four  and  one  half  times  that  of 
the  steam  in  the  live  steam  connection. 

It  is  due  to  this  higher  velocity,  bad  bends  in  the  line  and  other 
friction  losses  that  the  vacuum  at  the  engine  is  in  many  cases  so 
much  less  than  at  the  condenser.  In  steam  turbine  practice  where 
an  extremely  high  vacuum  is  maintained,  i  cu.  ft.  of  boiler  steam 
will  expand  to  a  volume  of  about  130  cu.  ft.  in  28  in.  of  vacuum. 
Therefore  the  diameter  of  the  exhaust  should  be  eleven  times  that 
in  the  steam  lines  to  maintain  the  same  velocity  as  that  of  the  boiler 
steam.  If  it  were  possible  to  reduce  the  velocity  of  the  vacuum 
steam  by  using  larger  lines,  then  it  would  also  be  possible  to  use  a 
longer  pipe  line  with  the  condenser  located  in  a  more  advantageous 
position.  By  way  of  illustration  a  lo-in.  steam  line  under  the  stated 
conditions  would  require  a  vacuum  exhaust  line  9  ft.  in  diameter. 

170 


VACUUM   EXHAUST  PIPING.  If  I 

It  has  been  found  practical  to  pipe  only  the  smaller  turbines  into 
a  high- vacuum  main.  The  economies  of  the  different  vacuums 
have  been  determined  by  actual  tests,  and  the  engineer  is  therefore 
able  to  determine  how  much  yearly  loss  he  will  think  justifiable  in 
order  to  effect  any  desired  piping  system.  For  large  units  using 
higher  vacuums  the  type  of  construction  affording  the  highest 
vacuum  and  the  least  resistance  to  the  flow  of  steam  is  the  one  most 
desirable.  Not  only  should  the  connections  be  short  and  of  a 
large  diameter  but  the  shape  of  the  mouth  and  discharge  openings 
should  also  be  properly  designed,  as  the  loss  between  the  turbine 
and  condenser  can  often  be  reduced  one  third  by  so  doing.  The 
loss  of  i  in.  in  vacuum  on  a  compound  engine  causes  an  increase 
in  the  steam  consumption  of  less  than  i  per  cent,  but  the 
loss  of  i  in.  from  28  to  27  in.  of  vacuum  on  a  steam  turbine 
increases  the  steam  consumption  about  6  per  cent.  It  would 
therefore  be  possible  to  design  a  vacuum  main  for  engine  work 
that  would  be  quite  impracticable  for  use  with  turbines. 

The  friction  losses  should  also  be  reduced  as  much  as  possible  in 
the  vacuum  lines.  A  i,5oo-kw.  unit  will  in  most  cases  generate 
about  9,000,000  kw-hr.  per  year,  the  generating  cost  for  labor  and 
fuel  being  about  $60,000  per  year.  This  would  mean  a  yearly  loss 
of  $600  for  each  inch  of  vacuum  lost  by  friction.  This  sum  would 
pay  the  interest  and  depreciation  on  an  additional  investment  of 
$6,000  to  cover  the  necessary  cost  of  larger  piping,  which  would 
reduce  the  loss  i  in.  The  increased  cost  to  reduce  this  friction 
loss  would  in  most  cases  be  comparatively  slight,  being  possibly 
the  expense  of  more  careful  study  in  laying  out  the  original  system. 

But  little  useful  data  is  available  to  determine  the  amount  of  the 
losses  through  the  fittings,  valves,  etc.,  required  in  the  different  pipe 
lines.  The  branch  from  the  vacuum  main  should  be  short  to  avoid 
line  loss ;  to  care  for  expansion  this  connection  should  be  long,  as  in 
the  case  where  but  two  pieces  of  apparatus  are  tied  to  the  main.  To 
comply  with  these  conflicting  demands  a  compromise  is  necessary. 
The  amount  of  strain  that  can  be  safely  placed  on  pipe  work  has 
not  been  sufficiently  determined  to  be  useful  in  making  calculations. 

The  details  used  in  providing  for  expansion  other  than  that  of 
the  pipe  itself  are  invariably  some  form  of  elastic  joint  or  pipe. 
Fig.  141  (Bi-i)  shows  a  diaphragm  joint  made  of  steel  plate, 
riveted  and  calked.  This  joint  has  been  found  very  satisfactory 
for  use  on  large,  riveted  mains.  Such  riveted  work  is  used  exten- 


1/2 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


sively  for  large  exhaust  and  vacuum  pipes.  It  is  not  the  riveted 
work  that  is  especially  wanted,  but  the  increased  size  of  the  mains. 
Fig.  142  (Bi-2)  shows  one  of  a  variety  of  forms  of  diaphragm 
joints  used  on  welded  pipe  and  made  in  the  pipe  shops.  The  form 
shown  in  Fig.  142  is  a  design  which  must  be  made  in  the  pipe  shop 
and  should  be  assembled  by  the  pipe  fitter.  The  form  illustrated 


FIG.  141  (Br-i). 


FIG.  142  (61-2). 


in  Fig.  141  should  be  made  in  the  boiler  shop  and  assembled  by  the 
boiler  maker.  If  the  large  mains  are  made  in  the  boiler  shop  it 
will  be  found  advantageous  to  have  the  boiler  makers  assemble 
and  erect  them.  The  practice  of  riveting  heavy  flanges  to  the 
shell  of  the  pipe  is  not  considered  good  detail  work,  whether  the 
flanges  be  made  of  cast  iron  or  steel.  The  best  boiler  shop  prac- 
tice is  to  rivet  together  sheets  of  like  thickness  and  allow  the  riveted 
joints  to  be  as  flexible  as  possible.  The  form  shown  in  Fig.  141 
is  considered  good  boiler  shop  practice  since  it  affords  an  oppor- 
tunity for  applying  the  rivets  and  for  driving  and  calking  the 
joints,  all  the  rivets  being  short. 

To  avoid  such  a  design  as  is  shown  in  Fig.  143  (61-3),  where 
the  pipe  lines  connect  to  the  flanged  faces  of  the  machines,  the  con- 
nection as  illustrated  by  Fig.  144  (61-4)  should  be  used.  The 
portion  a  should  be  made  of  steel  plate  about  12  in.  wide  and  with- 
out a  straight  seam.  The  lap  edges  of  the  plate  should  be  welded 
before  the  flange  is  turned  over.  The  holes  should  be  punched  in 
the  circular  seam  b  for  the  plate  a  only.  The  end  of  the  section  c 
should  be  left  long  and  the  rivets  in  d  omitted  for  a  distance  of 


VACUUM  EXHAUST  PIPING. 


173 


about  a  foot  from  b  until  the  circular  seam  is  riveted.  The  sec- 
tion a  should  be  bolted  in  place  and  c  be  in  position  before  mark- 
ing off  the  holes  in  the  seam  b  at  the  end  of  section  c.  If  the 
flange  end  of  a  be  turned  over  on  a  faced  forming  block  and  a 
wooden  maul  be  used  to  drive  the  flange  over  and  a  true  flatter 


OOQO 

!§ 


a. 


FIG.  143  (61-3). 


FIG.  144  (Bi-4). 


be  used  to  finish  the  face  after  it  is  turned  down,  it  will  not  be 
necessary  to  face  the  joint  e,  since  the  unevenness  will  be  very 
slight. 

In  a  design  as  shown  in  Fig.  145  (61-5)  the  expansion  and  con- 
traction would  be  taken  up  by  a  side  movement  of  the  different  sec- 


FIG.  145  (Bi-s). 

tions.  Fig.  146  (Bi-6)  shows  a  diagram  in  which  the  position  of 
the  parts  when  cold  is  indicated  by  solid  lines  and  when  heated,  by 
dotted  lines.  The  difference  in  position  of  the  parts  when  cold  and 
hot  as  indicated  by  a  may  be  assumed  as  i  in.,  the  joint  b  be- 


174 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


ing  on  a  36-in.  pipe.  The  radius  of  the  pipe  being  18  in.  and  the 
swinging  section  96  in.  long,  the  movement  at  the  joint  b  will  be 
18-^96  in.  of  compression  on  one  side  and  the  same  amount  of  ten- 
sion on  the  other,  there  being  no  movement  at  the  top  and  bottom 


w_ 

—  ^— 

=3                                                                                                                       = 

•"••  r                                                                          ^— 
v 

i 
* 

i 

=a. 

-•=? 

I 

V- 

•••• 

"  l 
1 

H 
H' 

:^r«-/" 

1 
1 

FIG.  146  (Bi-6). 

of  the  diaphragm.  The  movement  at  the  joint  b  would  be  T36  in. 
or  s3j  in.  on  each  of  the  diaphragm  plates.  Unless  some  such  pro- 
vision as  is  here  shown  be  made  for  the  expansion  strain,  much 
trouble  will  be  caused  by  leaks  throughout  the  riveted  work. 


FIG.  147  (61-7). 

In  case  the  line  be  made  of  regular  welded  pipe  with  flanged 
fittings  the  strain  can  be  similarly  taken  care  of  with  corrugated 
copper  connections  as  is  shown  in  Fig.  147  (61-7).  The  flange  a 
should  be  made  of  wrought  iron,  steel  or  a  steel  casting  because 
corrugated  copper  expansion  joints  are  quite  expensive  and  it  be- 


VACUUM  EXHAUST  PIPING.  175 

comes  very  difficult  to  make  repairs  in  case  of  the  breaking  of  the 
cast-iron  flange.  If  the  joints  are  to  be  ordered  it  should  be  speci- 
fied that  they  be  made  of  steel,  as  it  is  customary  to  furnish  such 
joints  with  cast-iron  flanges.  The  joint  faces  of  fittings  and  flanges 
should  be  made  with  an  adhesive  gum  packing  which  should  be 
preferably  free  from  graphite,  so  that  in  case  the  pressure  on  the 
gasket  is  released,  there  will  be  no  danger  of  a  portion  of  the 
gasket  being  sucked  into  the  pipe  by  the  vacuum. 

A  simple  method  of  preventing  the  gasket  from  being  drawn  into 
the  pipe  is  to  make  the  edge  of  the  raised  joint  face  as  is  shown  in 
Fig.  148  (Bi-8)  and  let  the  outside  diameter  of  the  gasket  be  the 
diameter  inside  of  the  bolts.  The  gasket  will  have  a  thick  edge  on 


FIG.  148  (Bi-8).  FIG.  149  (61-9). 

the  outside  of  the  joint,  shown  at  a,  due  to  its  compression  on  the 
joint  faces  only.  The  shoulder  on  the  gasket  should  be  formed 
gradually  without  any  perceptible  angle  and  not  as  shown  in  Fig. 
149  (Bi-g),  which  practice  causes  a  weak  point  in  the  gasket  where 
the  bead  and  the  compressed  portion  join.  This  weakness  may  not 
show  for  a  considerable  time,  probably  not  until  the  gasket  becomes 
hard  and  brittle  from  the  heat  of  the  steam  or  soft  and  gummy 
from  the  effects  of  the  cylinder  oil.  Cloth  insertion  or  rubber 
packing  is  not  as  suitable  for  gaskets  on  a  vacuum  line  as  some 
adhesive  type  of  packing. 

The  valves  for  vacuum  lines  are  invariably  of  the  gate  pattern, 
and  in  order  to  give  satisfactory  service  they  should  be  what  is 
commonly  styled  the  loo-lb.  pressure  valve.  The  so-called  "  light- 
pattern  "  exhaust  valves  are  not  rigid  enough  to  maintain  their  per- 
fect form  under  excessive  expansion  strains  and  do  not  permit  of 
their  being  closed  air-tight.  In  the  general  arrangement  diagrams, 
Figs.  47  and  48,  the  vacuum  lines  are  shown  and  each  engine  is 
provided  with  a  shut-off  valve.  When  the  load  drops  from  the 
engine  it  is  advisable  to  provide  some  means  of  quickly  opening  or 
closing  this  shut-off  valve  to  prevent  the  engine  from  running  above 
normal  speed.  The  operating  device  should  be  placed  close  to 
the  steam  throttle.  A  wattmeter  should  be  provided  for  each 


1/6  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

generating  unit,  located  on  the  gage  board  or  at  a  place  where  it 
can  be  clearly  seen  from  the  operator's  position  while  at  the  engine 
throttle.  The  exhaust  valve  may  be  operated  by  a  small  motor 
or  by  a  hydraulically-driven  piston.  The  wattmeter  shows 
instantly  when  the  load  is  thrown  on  the  machine  and  whether  the 
load  is  being  increased  or  diminished,  thereby  enabling  the  opera- 
tor to  regulate  the  steam  and  vacuum  valves  accordingly. 

The  value  of  a  wattmeter  at  the  engine  has  been  so  fully  demon- 
strated that  where  it  has  been  installed,  the  attendant  is  often 
guided  more  by  it  than  by  the  steam  or  vacuum  gage.  He  keeps 
a  constant  watch  on  the  wattmeter  and  intermediate  gage  and 
raises  the  intermediate  pressure  when  he  sees  that  the  load  on  the 
engine  is  increasing.  The  wattmeter  at  the  engine  has  nothing  to 
do  with  switchboard  work  or  with  the  electrical  control.  It  merely 
shows  the  attendant  what  work  the  engine  must  do  and  makes 
his  duty  more  definite. 

Where  there  are  two  or  three  large  engines  on  a  condenser  and 
the  load  is  liable  to  drop  off  instantly  there  is  always  a  possi- 
bility that  the  engines  will  run  away.  To  avoid  this  it  is  quite 
necessary  to  break  the  vacuum  as  soon  as  possible.  On  account 
of  the  large  volume  of  steam  at  a  rather  high  pressure  in  the  low- 
pressure  intermediate  receiver  it  is  not  sufficient  to  close  the 
steam  throttle.  Even  though  the  main  throttle  be  instantly 
closed  when  the  load  falls  off  the  engine  it  will  be  some  time 
before  the  pressure  in  the  intermediate  receiver  is  lowered  through 
the  low-pressure  cylinder.-  The  automatic  stop  valves  furnished 
by  engine  builders  are  not  as  a  rule  sufficient  to  save  the  engine. 
A  i,5oo-kw.  unit  might  be  in  parallel  with  other  machines  run- 
ning condensing  and  developing  500  kw.  with  the  automatic 
butterfly  valve  closed.  This  entire  load  would  be  carried  by 
the  low-pressure  side  alone.  By  observing  the  wattmeter  and 
tachometer  on  an  engine  it  will  be  noted  that  the  highest  engine 
speeds  occur  when  very  light  loads  follow  the  heavy  loads.  This 
situation  occurs  in  its  most  severe  form  when  an  engine  has  been 
very  much  overloaded,  thereby  throwing  the  breaker  and  losing 
its  entire  load  in  less  than  one  revolution.  The  attendant  should 
be  able  to  at  once  throw  a  switch  on  the  engines  and  close  the 
vacuum  valve. 

For  two  reasons  it  is  quite  out  of  the  question  to  operate  large 
vacuum  valves  by  hand.  First,  because  it  takes  so  long  to  oper- 


VACUUM  EXHAUST  PIPING. 


'77 


ate  the  valves  by  hand  that  much  harm  may  be  done  elsewhere 
before  the  operator  can  get  away.  Second,  because  after  quickly 
closing  say  a  30  or  36-in.  valve  the  operator  is  in  no  condition 
to  do  anything  else  for  a  time,  since  the  handling  of  these  large* 
valves  requires  the  expenditure  of  considerable  energy.  Referring 
again  to  Fig.  48,  it  will  be  noted  that  the  vacuum  stop  valves  for  each 
engine  are  so  situated  that  it  would  be  extremely  difficult  to  reach 
them  while  controlling  an  engine.  By  using  a  motor-operated  valve, 
the  switch  controller  may  be  placed  wherever  it  is  most  convenient. 

The  atmospheric  valve  should  also  be  given  full  consideration  in 
connection  with  engine  control  as  it  must  operate  in  unison  with 
the  vacuum  gate  valve.  In  Fig.  150  (Bi-io)  is  shown  the  gen- 
eral form  of  an  atmospheric  relief  valve  of  the  vertical  type.  The 
dash  pot  is  placed  on  the  outside  where  it  can  be  inspected,  cleaned 
or  repaired  while  the  valve  is  in  use.  This  type  of  valve  is  suit- 
able for  plants  that  are  to  be  well  maintained.  If  they  are  not  to 
be  well  kept  it  would  be  advisable  to  use  an  interior  type  of  dash 
pot,  using  condensation  in 
the  dash  pot  instead  of  oil  as 
would  be  the  case  with  the 
exterior  type  of  pot.  An  oil 
dash  pot,  when  in  good  order, 
will  operate  very  satisfactorily, 
but  if  it  is  allowed  to  become 
gummed  or  clogged  with 
dust  and  dirt  its  smooth 
working  will  be  greatly  inter- 
fered with.  The  stuffing  box 
of  the  valve  shown  in  Fig.  150 
may  be  loosely  packed,  as  it  is 
on  the  atmospheric  side  of 
the  valve.  The  atmospheric  valve  should  be  provided  with  tapped 
openings  say  three-eighths  or  one-half  in.  in  diameter  for  a  small 
water  connection  and  an  overflow.  These  connections  are  valuable 
in  determining  whether  or  not  the  valve  leaks,  and  in  showing  the 
amount  of  leak,  and  in  preventing  air  from  leaking  into  the  vacuum 
line.  Without  this  connection  it  is  very  difficult  to  determine 
whether  or  not  the  valve  leaks  air. 

One  of  the  most  approved  forms  of  the  interior  dash-pot  type 
of  atmospheric  valve  is  shown  in  Fig.  151  (Bi-n).     This  is  of 


FIG.  150  (Bi-io). 


17* 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


the  horizontal  type.  The  opening  a  is  for  the  small  water  con- 
nection, while  the  opening  b  is  for  the  overflow.  The  flange  c  is 
provided  to  retain  water  over  the  valve  face.  The  hand  wheel  and 
screw  shown  at  d  are  used  to  raise  the  valve  from  its  seat  as  would 
be  required  if  it  were  running  non-condensing  for  a  considerable 


FIG.  151  (Bi-u). 

time.  The  valve  shown  in  Fig.  150  should  have  a  side  plate  that 
can  be  removed  in  case  it  is  necessary  to  regrind  the  valve  to  its 
seat.  The  valve  shown  in  Fig.  151  can  be  readily  reground  by 
removing  the  top  cap.  The  guide  can  be  held  in  place  by  using 
blocks  under  the  heads  of  the  screws. 

Atmospheric  valves  are  subjected  to  rather  extreme  demands, 
the  requirement  being  a  tight  valve  with  but  little  pressure  on  the 
seat  face.  These  valves  can  be  ground  in  and  made  tight  in  the 
shop,  but  in  most  cases  after  they  have  been  put  into  service  they 
will  soon  show  bad  leaks.  This  condition  is  quite  unavoidable  and 
can  hardly  be  called  a  defect.  The  body  of  the  valve  is  a  heavy 
casting  in  which  the  molding  strains  are  relieved  by  subjecting  it 
to  the  steam  temperature.  At  the  end  of  a  week's  run  the  valve 
may  leak  badly,  and  after  grinding  it  may  be  perfectly  tight.  Then 
at  the  end  of  a  month's  run  it  may  again  show  some  leak  and 
require  regrinding.  It  may  not  then  show  any  perceptible  leak 
for  a  year  or  more.  The  tendency  of  a  casting  is  to  relieve  itself 


VACUUM   EXHAUST   PIPING. 


179 


of  the  molding  strain,  and  each  time  the  valve  is  reground  it  is  in 
better  shape  than  before.  There  does  not  seem  to  be  any  practical 
way  of  overcoming  this  difficulty. 

There  is  another  type  of  atmospheric  valve,  illustrated  in  Fig. 
152  (Bi-i2),  which  is  frequently  furnished  by  the  engine  builders. 
This  valve  is  intended  to  be  positively  operated  by  hand  instead  of 


FIG.  152  (Bi-i2). 

being  automatic  in  closing.  The  valve  must  be  held  in  position 
on  its  seat  until  vacuum  has  been  introduced  on  the  line,  after 
which  the  valve  will  be  held  shut  by  reason  of  the  difference  in 
pressure  due  to  the  vacuum.  In  case  the  vacuum  valve  is  motor 
operated  it  can  be  thrown  in  and  the  atmospheric  valve  partially 
closed  with  the  hand  lever.  The  operator  will  then  be  able  to 
ascertain,  by  feeling,  when  the  vacuum  is  increasing  in  the  line,  and 
can  force  the  valve  to  its  seat  and  hold  it  closed. 
With  this  valve,  the  objectionable  feature  of  chattering  can  be 


ISO  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

practically  eliminated.  There  is  nothing  that  injures  the  valve 
faces  of  an  atmospheric  valve  as  much  as  this  continuous  chat- 
tering. On  valves  of  20-in.  diameter  and  over,  the  chattering 
becomes  particularly  severe.  A  20-in.  valve  will  have  an  area  of 
314  sq.  in.,  and  if  the  travel  of  the  valve  is  5  in.  and  that  of  the 
hand  lever  30  in.,  it  would  be  possible  to  hold  the  valve  against  a 
i-lb.  back  pressure  or  2  in.  of  vacuum  by  exerting  a  pressure  of 
50  Ib.  on  the  lever.  There  are  some  objections  to  this  valve,  one 
being  that  it  is  a  difficult  valve  to  regrind  and  keep  in  perfect 
alignment  with  its  face.  This  is  a  fault  common  to  all  beat  valves 
which  lie  on  their  sides.  Another  objection  is  that  a  water  seal 
cannot  be  used  to  shut  off  any  leaks  which  may  occur. 

There  are  certain  essential  features  that  an  atmospheric  valve 
should  possess  to  meet  the  requirements  in  the  most  efficient 
manner:  The  valve  should  be  of  the  beat  form;  the  valve  face 
should  be  placed  in  a  horizontal  position;  a  water  seal  should  be 
provided  for  the  valve  seat;  a  cap  plate,  which  may  easily  be 
removed,  should  be  provided  to  facilitate  inspection  or  regrind- 
ing;  the  valve  should  be  rotatable  with  respect  to  its  operating 
lever  or  guides,  so  that  the  same  device  that  is  used  to  raise  the 
valve  from  its  seat  will  be  an  aid  in  regrinding;  when  the  cap 
plate  is  removed  all  the  valve  guides  should  be  in  place  to  allow 
a  proper  regrinding;  the  dash  pot  should  be  of  such  a  form  and  so 
located  that  it  can  readily  be  inspected  and  kept  in  good  order, 
and  some  means  should  be  provided  for  holding  the  valve  off  its 
seat  when  the  engine  is  to  be  run  non-condensing. 

The  sizes  of  an  atmospheric  valve  and  pipe  may  be  con- 
siderably less  than  those  of  similar  parts  on  a  vacuum  line 
because  of  the  difference  in  the  volumes  of  steam  at  atmospheric 
pressure  and  under  vacuum.  The  volume  of  a  given  amount  of 
steam  at  26  in.  of  vacuum  is  seven  times  that  of  the  same  steam 
at  atmospheric  pressure.  It  is  thus  seen  that  the  area  of  the 
atmospheric  connections  can  be  made  one-seventh  the  size  of 
those  for  the  vacuum  line  and  still  maintain  the  same  velocity  of 
flow.  There  would,  however,  be  but  a  slight  loss  in  case  the 
velocity  flows  varied,  since  the  atmospheric  connection  is  in  use 
but  a  small  portion  of  the  time. 

For  fixing  the  relative  dimensions  of  the  different  engine  con- 
nections of  a  compound  engine,  so  that  the  flow  will  be  the  same 
at  all  parts,  the  following  argument  should  be  considered : 


VACUUM   EXHAUST  PIPING. 


181 


The  volume  of  live  steam  at  160  Ib.  pressure  which  would  flow 
into  the  high-pressure  cylinder  for  one-quarter  of  the  stroke 
until  cut  off  may  be  arbitrarily  assumed  as  i.  The  steam  in 
the  high-pressure  cylinder  will  expand  its  volume  six  times  in 
exhausting  to  the  receiver,  but  as  the  flow  from  the  live  steam 
main  into  the  high-pressure  cylinder  was  cut  off  after  one-quarter 
of  the  stroke,  and  as  the  exhaust  to  the  receiver  takes  place  dur- 
ing the  full  stroke,  the  relative  areas  of  the  admission  and  exhaust 
ports  are  not  as  i  is  to  6,  but  as  i  is  to  6  -^  4;  or  the  exhaust 
port  should  have  an  area  1.5  times  that  of  the  admission  port. 
As  the  steam  in  the  receiver  has  expanded  to  six  times  its  original 
volume  in  the  high-pressure  cylinder,  the  admission  valves  of  the 
low-pressure  cylinder,  in  order  to  maintain  the  same  velocity  flow, 
should  have  an  area  of  six  times  the  admission  valves  to  the  high- 
pressure  cylinder,  since  the  valves  of  both  cylinders  cut  off  at  one- 
quarter  stroke.  If  the  low-pressure  cylinder  exhausts  to  26  in. 
of  vacuum,  the  steam  in  the  condenser  will  occupy  72  times  the 
volume  it  did  in  the  high-pressure  cylinder  up  to  the  time  of  cut- 
off, but  as  the  exhaust  ports  of  the  low-pressure  cylinder  are 
open  to  the  condenser  during  the  full  stroke  and  the  admission 
ports  from  the  receiver  to  the  low-pressure  cylinder  are  open 
but  one-quarter  of  the  stroke,  the  necessary  area  to  maintain  an 
even  flow  will  be  one-quarter  of  72,  or  18  times  the  area  of  the 
live-steam  ports  of  the  high-pressure  cylinder.  In  case  the  engine 
exhausts  to  atmosphere  the  relative  volume  of  live  steam  to  steam 
at  atmospheric  pressure  will  be  as  i  to  10,  but  the  live  steam 
flows  into  the  engine  only  one-quarter  of  the  time  and  the  exhaust 
steam  flows  to  atmosphere  during  the  full  stroke.  Therefore, 
instead  of  the  atmospheric  valves  having  an  area  ten  times  as 
great  as  that  of  the  admission  valves,  the  area  need  be  but  2.5 
times  as  large  to  maintain  the  same  velocity  of  flow.  The  fore- 
going argument  reduced  to  diameters  appears  as  follows : 


Pres- 
sure Ib. 

Volume. 

Area. 

Dia- 
meter. 

160 

Steam  to  the  High-Pressure  Cylinder  

I 

I 

IO 

Exhaust  from  the  High-Pressure  Cylinder  

6 

1.5 

1.22 

10 

Steam  to  the  Low-Pressure  Cylinder  

6 

6 

2-45 

o 

Exhaust  from  the  Low-Pressure  Cylinder  

10 

2-5 

I..S8 

26* 

Exhaust  from  the  Low-Pressure  Cylinder  

72 

18 

4.24 

*  Inches  of  vacuum. 


1 82  STEAM   POWER  PLANT  PIPING  SYSTEMS. 

Following  this  argument,  if  the  steam  line  is  10  in.  in  diameter, 
the  exhaust  to  the  receiver  will  be  n\  in.  in  diameter  and  the 
steam  line  to  the  low-pressure  cylinder  will  be  24  in.  in  diameter. 
The  atmospheric  exhaust  will  be  16  in.  in  diameter.  The 
vacuum  exhaust  is  usually  made  by  the  engine  builders  twice  the 
size  of  the  live-steam  line,  giving  the  exhaust  steam  a  velocity  four 
times  that  of  the  live  steam,  instead  of  42  in.  and  the  same  velocity. 

The  tendency  in  engine  building  is  to  make  the  connections  to 
the  high-pressure  side  of  an  engine  larger  and  to  the  low-pressure 
side  smaller  than  is  necessary.  In  receiving  bids  for  engines,  the 
engine  builder  should  be  required  to  state  the  size  of  the  port 
openings,  as  the  efficiency  of  an  engine  is  considerably  affected 
by  the  frictional  losses  in  the  restricted  area  of  the  low-pressure 
ports.  The  atmospheric  connection  can  consistently  be  made 
three-eighths  of  the  diameter  of  the  vacuum  exhaust  and  still 
maintain  the  same  velocity  of  flow  in  the  atmospheric  connection 
as  in  the  vacuum  connection.  In  other  words,  a  g-in.  atmos- 
pheric pipe  could  be  used  in  connection  with  a  24-in.  vacuum 
line.  This  ratio  is  rather  extreme  in  practice  and  it  is  not  used. 
The  low-pressure  port  opening  in  the  exhaust  valve  of  a  com- 
pound engine  having  a  i2-in.  live-steam  connection  will  have  an 
area  of  5  by  64  in.  or  320  sq.  in.  This  is  2.83  times  the  area  of 
the  steam  pipe  and  corresponds  to  a  diameter  of  1.68  when  the 
diameter  of  the  live-steam  port  is  i.  It  will  be  noted  that  this 
area  is  but  slightly  greater  than  that  required  to  exhaust  to  the 
atmosphere  and  maintain  the  same  velocity  for  the  exhaust  as 
for  the  live  steam.  If  the  port-ways  in  the  low-pressure  cylinder 
are  made  larger,  the  cost  of  the  low-pressure  cylinder  will  be 
materially  increased. 

Class  B3  —  Vacuum  Exhaust  to  Condenser.  With  an  elevated 
jet  condenser  installation  it  is  a  rather  general  practice  to  place  an 
entrainer  at  the  lower  end  of  the  riser  to  the  condenser  as  shown 
in  Fig.  153  (63-1).  The  principle  of  the  entrainer  is  that 
instead  of  the  water  of  condensation  lying  at  the  bottom  of  the 
entire  vacuum  main,  the  condensation  flows  into  the  trap-shaped 
fitting  and  congests  the  passageway  for  the  steam  to  such  an  extent 
that  the  steam  will  pick  up  the  water  and  carry  it  up  and  into  the 
condenser.  But  very  little  condensation  will  be  held  in  the  trap 
before  it  fills  up  to  a  point  where  the  steam  will  carry  it.  Instead 
of  allowing  a  long  main  to  become  partially  filled  with  condensation 


VACUUM   EXHAUST   PIPING. 


183 


on  light  loads,  which  condensation  is  later  picked  up  on  heavy 
loads  and  thrown  against  the  elbows  of  the  main,  the  entrainer 
allows  but  little  water  to  lie  in  any  part  of  the  line.  It  is  of  course 
necessary  that  the  main  be  given  a  pitch  toward  the  entrainer. 
This  method  of  removing  condensation  has  been  found  very 
satisfactory. 

Another  method  of  removing  the  drips  from  a  vacuum  main  is 
by  means  of  a  vacuum  trap.     A  vacuum  trap  is  quite  interesting 


FIG.  153  (B3-i). 


FIG.  154  (B4-i). 


in  its  intricacies  of  steam,  drip,  and  discharge  connections,  and  also 
in  its  automatic  arrangement  for  opening  and  shutting  these  con- 
nections at  the  proper  time,  but  as  a  power  station  appliance  a 
vacuum  trap  is  considered  a  troublesome  device;  usually  some 
means  other  than  the  use  of  such  traps  can  be  devised  to  drain 
the  lines  if  the  idea  is  kept  in  mind  while  laying  out  the  vacuum 
system.  If  other  disposition  of  condensation  has  not  been  pro- 
vided for,  a  vacuum  trap  should  be  used  as  a  last  resort.  It  is  the 


1 84  STEAM   POWER   PLANT  PIPING  SYSTEMS. 

elimination  of  such  devices  that  shows  careful  and  competent 
station  engineering. 

Class  B4  —  Vacuum  Exhaust ;  Grease  Extractor.  The  usual 
type  of  grease  extractor  has  the  same  form  as  a  steam  separator. 
The  oil  carried  with  the  steam  is  in  combination  with  the  condensed 
vapors.  The  principle  of  operation  of  the  separator  is  to  lessen 
the  velocity  of  the  steam  before  changing  its  direction  of  flow  and 
thus  allow  the  heavier  particles  of  grease  to  continue  in  the  same 
direction  as  when  entering  the  separator  and  be  deposited  on  a 
"baffle"  which  is  out  of  the  path  of  the  steam. 

Fig.  154  (64-1)  illustrates  the  general  principle  of  all  grease 
extractors  with  a  few  minor  changes  in  the  location  of  the  baffles. 
There  is  no  current  in  the  space  indicated  by  a,  since  the  ribs  on 
the  baffle  prevent  any  flow  across  its  face.  A  water  spray  is  intro- 
duced through  the  pipe  shown  at  b,  which  further  reduces  the  tem- 
perature of  the  mist  on  the  baffle  and  conveys  it  down  to  the  drain 
pipe  shown  at  c.  The  lip,  d,  -is  provided  to  prevent  oil  from  creep- 
ing on  the  inner  surface  of  the  separator,  which  might  be  due  to 
the  flow  of  the  impinging  steam,  and  being  carried  to  the  condenser. 
The  water  spray  is  also  connected  with  this  ring.  The  spaces 
indicated  by  e  and  ef  are  the  passages  for  the  steam.  The  drain,  c, 
is  run  to  a  vacuum  trap  or  an  en  trainer.  The  drain,  c,  is  one  that 
should  not  be  carried  to  the  condenser,  and  in  order  to  eject  water 
the  entrainer  is  quite  necessary.  The  discharge  from  the  entrainer 
should  go  to  a  sewer  or  to  a  large  grease  trap.  If  a  grease  trap  is 
used,  all  drips  containing  any  oil  should  be  run  into  the  same 
system  throughout  the  plant.  This  system  will  be  described  more 
fully  in  a  later  chapter. 

With  surface  condensers  the  oil  is  removed  from  all  the  exhaust 
steam,  since  all  the  condensation  is  returned  to  the  boilers.  How- 
ever, if  jet  condensers  are  used,  it  is  quite  difficult  to  remove  the 
oil  from  all  of  the  exhaust  and  quite  useless  since  only  from  three 
to  five  per  cent  of  the  exhaust  steam  is  returned  to  the  boiler,  the 
remainder  being  discharged  with  the  tail  water  from  the  condenser 
to  the  stream  from  which  the  water  is  taken.  If  a  cooling  pond  or 
tower  is  used,  all  exhaust  steam  should  be  run  through  a  vacuum 
separator.  Unless  this  is  done,  the  greater  portion  of  the  cylinder 
oil  will  be  discharged  into  the  cooling  pond  or  tower.  The  inter- 
est on  an  investment  for  grease  extractors  will  be  recovered  by  the 
lessening  of  boiler  repairs  and  by  the  reclaiming  of  oil  and  grease. 


VACUUM   EXHAUST   PIPING. 


I85 


The  reclaimed  grease  cannot  be  used  again  in  the  oiling  system,  but 
there  are  many  other  valuable  uses  to  which  it  can  be  put. 

For  a  jet  condensing  plant,  a  very  efficient  arrangement  is  to  use 
a  small  elevated  jet  condenser  for  the  boiler  feed  water  only. 
There  may  be  two  large  station  condensers  for  a  station  generating 


FIG.  155  (64-2). 

120,000  Ib.  of  steam  per  hour  and  a  small  condenser  that  will 
circulate  120,000  Ib.  of  cooling  water  per  hour  or  at  a  rated  capacity 
of  4,000  Ib.  of  steam  per  hour.  This  latter  would  be  about  one- 
thirtieth  of  the  capacity  of  the  entire  plant.  This  small  condenser 


1 86  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

may  have  air  taken  from  it  through  the  regular  air  main  used  for 
the  main  condensers.  The  small  condenser  would  have  only  the 
feed  water  passing  through  it,  and  the  hot-well  water  would  be 
maintained  at  a  high  temperature,  possibly  10  degrees  higher  than 
in  the  large  condenser.  The  oil  could  be  eliminated  from  this 
condenser  by  using  the  grease  extractor  as  shown  in  Fig.  155 
(84-2). 

If  the  plant  is  supplied  with  two  3o-in.  condensers,  the  small 
condenser  should  have  an  8-in.  exhaust  connection,  about  a  4-in. 
circulating  water  connection,  and  a  5~in.  tail  pipe.  The  cost  of  this 
condenser  will  be  low  and  ordinarily  the  fuel  saved  will  more  than 
cover  the  increased  cost  of  installation.  Should  the  small  con- 
denser not  be  used  the  boiler  feed  water  would  have  to  be  handled 
in  the  large  condensers,  thereby  increasing  the  capacity  of  the  plant 
in  condenser  capacity.  No  extra  pumps  or  machines  are  required 
to  operate  the  small  condenser.  The  double-water-end  pump 
would  be  required  in  any  case.  If  the  condenser  is  not  used,  the 
low-pressure  pump  would  be  used  as  the  heater  pump.  The 
by-pass  connection,  shown  at  a,  is  used  when  the  condenser  is  not 
in  operation.  Due  to  the  float  valve  closing  the  discharge  to  the 
heater,  the  small  amount  of  surplus  hot-well  water  will  discharge 
through  the  overflow.  To  avoid  the  use  of  an  en  trainer,  the  drips 
from  the  grease  extractor  may  be  run  to  the  dry  vacuum  pump, 
since  there  will  be  but  one-thirtieth  part  of  the  steam  flowing  to  the 
small  condenser.  The  dry  vacuum  pump  will  handle  considerable 
moisture  without  causing  any  serious  difficulty. 

Class  B5  —  Vacuum  Exhaust  to  the  High-Pressure  Cylinder.  In 
Fig.  134  were  shown  the  steam  and  exhaust  lines  to  the  high 
and  low-pressure  cylinders  and  also  the  lines  to  the  condenser  and 
to  the  atmosphere.  The  valves  /  and  g  are  the  throttles  for  the 
high  and  low-pressure  sides  and  should  be  provided  with  floor 
stands  and  hand  wheels  close  to  the  valve  gear.  These  stands 
should  be  so  placed  as  not  to  interfere  with  the  removal  of  the 
valves  and  pistons.  The  valve  a  is  a  pressure-reducing  valve. 
The  valves  in  the  exhaust  from  the  high-pressure  cylinder  and  also 
the  one  next  to  the  low-pressure  cylinder  are  only  operated  when 
one  side  of  the  engine  is  out  of  service  and  the  other  side  is  to  be 
run  as  a  single-cylinder  engine.  Operating  devices  for  such  valves, 
running  through  the  floor,  are  neither  necessary  nor  desirable. 
The  valve  d  should  be  either  motor  or  hydraulically  operated. 


VACUUM  EXHAUST  PIPING.  187 

The  valve  e  is  the  'atmospheric  self-opening  and  closing  valve. 
The  valve  b  is  the  relief  valve  to  prevent  the  pressure  from  run- 
ning too  high  on  the  receiver. 

It  will  be  noted  that  the  receiver  is  used  when  the  low-pressure 
cylinder  is  operated  with  steam  passing  through  the  reducing  valve, 
and  also  that  the  reducing  valve  discharges  into  the  receiver  and 
not  into  the  line  to  the  low-pressure  cylinder.  These  two  features 
should  not  be  overlooked  because  otherwise  money  will  be  wasted 
for  these  low-pressure  connections  and  at  the  same  time  the  reduc- 
ing valve  could  not  be  operated. 

Reducing  valves  have  been  connected  to  low-pressure  cylinders 
without  receivers  and  have  failed  completely  in  controlling  the 
pressure.  There  must  be  a  large  volume  of  steam  between  the 
reducing  valve  and  the  cut-off  valve  of  the  engine  in  order  to 
avoid  the  constant  jumping  of  the  valve.  Usually  this  volume 
should  not  be  less  than  that  of  the  cylinder.  The  pipe  from  the 
receiver  to  the  low-pressure  cylinder  will  cause  a  greater  drop  in 
pressure  during  the  flow  of  steam  than  will  the  receiver.  In  order 
to  produce  a  more  steady  flow  through  it,  the  reducing  valve  should 
be  discharged  direct  to  the  receiver  and  not  into  the  branch  from 
the  receiver.  If  the  engine  has  no  receiver,  the  pressure-reducing 
valve  should  be  located  away  from  the  cylinder  as  far  as  would 
be  necessary  to  give  an  area  to  the  pipe  equal  to  the  area  of  the 
low-pressure  cylinder.  It  will  be  noticed  in  Fig.  134  that  the  high- 
pressure  cylinder  can  exhaust  either  to  the  condenser  or  to  the 
atmosphere  when  the  low  pressure  is  off,  and  that  the  low-pressure 
side  will  act  in  the  same  manner  when  the  high-pressure  side 
is  off. 

Class  B6  —  Vacuum  Exhaust  to  Auxiliaries.  In  most  cases  a 
condensing  plant  can  be  laid  out  so  that  only  the  pumps  and 
single-valve  engines  used  for  stokers,  stacks,  etc.,  will  exhaust  into 
the  heater.  These  machines  would  show  only  about  a  10  per  cent 
increase  in  power  if  they  were  run  condensing.  In  order  to  be 
able  to  determine  how  many  of  the  auxiliaries  should  be  run  to  the 
heater  or  to  the  condenser,  the  B.t.u.  losses  under  various  condi- 
tions and  when  run  condensing  and  to  the  heater  should  be  con- 
sidered as  follows: 

i.  If  live  steam  at  160  Ib.  pressure  is  fed  to  an  auxiliary  that 
exhausts  to  the  atmosphere,  it  will  require  1,195  B.t.u.  per  Ib.  of 
steam,  taken  as  one  unit  of  work. 


1 88  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

2.  If  live  steam  at  160  Ib.  pressure  is  fed  to  an  auxiliary  using 
90  per  cent  of  the  steam  when  run  condensing,  it  would  require 
1,075  B.t.u.  per  unit  of  work. 

3.  With  the  same  conditions  as  in  No.  2,  but  using  80  per  cent 
of  the  steam,  the  auxiliary  would  require  956  B.t.u.  per  unit  of  work. 

4.  With  the  same  conditions  as  in  No.  2,  but  using  70  per  cent 
of   the  steam,  the   auxiliary   would  require  836  B.t.u.  per    unit 
of  work. 

5.  If  live  steam  at  160  Ib.  pressure  is  fed  to  the  auxiliary,  deliv- 
ering 90  per  cent  in  exhaust  steam  and  10  per  cent  in  condensation 
to  the  heater,  it  would  require  146  B.t.u.  per  unit  of  work. 

6.  With  the  same  conditions  as  in  No.  5,  but  delivering  50  per 
cent  of  the  steam  to  the  heater  and  50  per  cent  to  the  atmosphere, 
the  auxiliary  would  require  622  B.t.u.  per  unit  of  work. 

7.  With  the  same  conditions  as  in  No.  5,  but  delivering  30  per 
cent  of  the  steam  to  the  heater,  the  auxiliary  would  require  802 
B.t.u.  per  unit  of  work. 

8.  With  the  same  conditions  as  in  No.  5,  but  delivering  10 
per  cent  of  the  steam  to  the  heater,  the  auxiliary  would  require 
i, 080  B.t.u.  per  unit  of  work. 

It  will  be  seen  from  the  foregoing  that  auxiliaries  using  a  large 
amount  of  steam  per  horsepower,  or  in  other  words,  auxiliaries 
that  show  but  a  slight  decrease  in  steam  consumption  when  run 
condensing,  are  most  economical  when  exhausting  to  the  heater. 
In  No.  2,  for  instance,  where  the  auxiliary  runs  condensing,  there 
is  required  the  consumption  of  as  many  heat  units  as  under  the 
conditions  illustrated  in  No.  8,  where  the  pump  uses  but  one-tenth 
of  its  steam  in  the  heater,  the  remainder  being  wasted  to  the 
atmosphere.  In  No.  4,  which  illustrates,  the  economy  of  a  com- 
pound condensing  unit,  the  consumption  of  heat  units  would  be 
less  if,  as  in  No.  7,  it  were  delivering  but  30  per  cent  of  its  steam 
to  the  heater  and  were  running  non-condensing. 

In  the  effort  to  secure  high  economy,  electrically  driven  auxilia- 
ries are  frequently  used,  the  idea  being  that  the  economy  of  the  aux- 
iliaries will  be  nearly  that  of  the  large  main  units.  For  example, 
an  electrical  auxiliary  may  require  through  its  main  unit  but  16  Ib. 
of  steam  per  horsepower,  which  at  1,195  B-t.u.  per  Ib.  would  be 
a  total  of  19,120  B.t.u.  per  hour.  If  a  steam  auxiliary,  run  non- 
condensing,  is  used,  all  of  the  exhaust  being  used  in  the  heater, 
as  in  No.  5,  the  consumption  would  be  146  B.t.u.  per  Ib.  of 


VACUUM   EXHAUST  PIPING.  189 

steam  or  14,600  B.t.u.  per  hour,  if  it  requires  100  Ib.  of  steam 
per  horsepower.  This  represents  a  saving  of  4,520  units,  which 
would  be  a  saving  in  steam  over  the  motor  drive  of  24  per  cent. 
The  question  now  arises  as  to  where  the  dividing  point  is  between 
operating  condensing  and  non-condensing  to  the  heater. 

In  the  first  place,  water  delivered  to  the  heater  at  from  90 
degrees  to  100  degrees,  as  would  be  the  case  from  the  hot-well 
delivering  the  water  at  210  degrees,  would  require  from  10  to 
ii  Ib.  of  exhaust  steam  for  each  100  Ib.  of  feed  water.  More 
than  this  amount  of  exhaust  could  not  be  condensed  and  the 
excess  would  waste  to  the  atmosphere.  The  auxiliaries  should 
be  arranged  to  furnish  all  their  exhaust  steam  to  the  heater  pro- 
vided this  exhaust  steam  does  not  exceed  from  10  to  11  per  cent 
of  the  whole  amount  of  steam  generated  by  the  boilers.  When 
the  exhaust  steam  is  wasting  to  the  atmosphere  an  amount  equal 
to  75  per  cent  of  the  whole  amount  delivered  by  a  compound 
engine  or  90  per  cent  of  that  delivered  by  a  pump,  it  will  then  be 
slightly  better  economy  to  connect  such  a  machine  to  a  con- 
denser. It  is  useless  to  connect  the  large  generating  units  to 
the  heater.  In  the  case  of  four  units,  there  would  be  25  per 
cent  of  the  steam  delivered  to  each  unit,  and  if  exhaust  could  not 
be  obtained  from  any  other  source,  it  would  then  be  necessary  to 
condense  30  per  cent  of  the  exhaust  in  the  heater  in  order  to 
equal  the  economy  of  the  condenser.  In  other  words,  7.5  per 
cent  of  the  station  steam  would  be  delivered  by  one  of  the  gen- 
erating units  alone.  When  the  auxiliaries  are  added  to  this, 
there  would  then  be  about  15  per  cent  of  the  steam  generated  to 
be  condensed  in  the  heater,  which  would  not  be  possible.  In 
most  cases,  not  more  than  10  per  cent  of  the  exhaust  of  one  of  the 
large  units  could  be  used,  and  if  the  exciter  engine  be  exhausted 
to  the  heater,  the  auxiliaries  being,  as  they  generally  are,  steam 
consumers,  no  additional  steam  can  be  condensed.  It  is  cus- 
tomary to  allow  about  10  per  cent  of  the  station  steam  for  the 
requirements  of  the  auxiliaries,  which  is  practically  all  that  the 
heater  will  take  economically. 

The  exciter  engine  should  be  piped  both  to  the  condenser  and 
to  the  heater  main  if  the  heater  is  able  to  condense  one-half  of 
the  steam  from  the  exciter  engine  together  with  that  from  all  the 
other  auxiliaries.  The  small  pumps,  stoker  engines,  etc.,  should  be 
connected  to  the  heater  main  only.  It  is  seldom  that  the  exhaust 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 

from  the  exciter  engine  cannot  be  condensed  in  the  heater,  and 
the  saving  effected  by  running  it  at  any  time  condensing  would  be 
very  slight.  Assuming  that  the  large  unit  uses  15  Ib.  of  steam  per 
horsepower-hour,  it  costs  not  less  than  i  per  cent  of  the  whole 
power  of  a  large  unit  to  operate  the  condensing  apparatus. 
Since  pumps  and  other  auxiliary  apparatus  require  from  six  to 
seven  times  this  amount  of  steam  per  horsepower-hour,  it  would 
require  from  6  to  7  per  cent  of  the  pump  power  to  operate 
condensing  machinery  that  will  effect  a  gross  saving  of  10  per 
cent,  leaving  a  net  saving  of  but  3  to  4  per  cent  in  the  steam 
consumption  of  the  pump.  The  amount  of  steam  available  in 
the  shape  of  pumps,  stoker  engines,  etc.,  should  be  determined 
and  also  the  possible  demands  in  the  shape  of  exhaust  steam  for 
the  heating  system.  It  can  then  be  better  determined  whether 
some  of  the  small  generating  machinery  is  to  be  arranged  to  run 
either  condensing  or  non-condensing. 

Another  detail   that  enters   into  the  consideration  of  exhaust 
steam  lines  is  the  exhaust  heating  system.     In  Fig.  156   (B6-i) 

is  shown  a  simple  arrangement 
of  the  exhaust  heating  system 
from  exciter  engines.  The 
valve  a  is  closed  when  the  heat- 
ing system  is  not  in  use,  and 
the  valve  b  is  open  when  the 
exciter  engines  are  run  condens- 
ing.  When  both  a  and  b  are 
FIG.  156  (B6-i).  closed,  the  exciter  engines  will 

exhaust   to   the  heater.    The 

back-pressure  valves  serve  both  for  atmospheric  relief  and  for  relief 
in  case  the  pressure  in  the  heating  main  exceeds  the  pressure  as 
set.  All  the  main  units  should  be  on  the  vacuum  main  and  all 
other  auxiliaries  should  be  on  the  heater  main.  In  laying  out  the 
station  the  machines  may  be  selected  and  arranged  so  that  they 
will  give  only  the  amount  of  steam  required  for  the  different 
classes  of  service.  This  is  another  instance  where  the  nature  of 
the  system  must  be  fully  determined  before  the  machinery  is  pur- 
chased or  in  any  way  decided  upon.  The  ideal  system  is  one 
which  will  deliver  to  the  heater  all  the  steam  it  will  condense  and 
at  the  same  time  not  waste  to  the  atmosphere  more  than  one- 
half  of  the  exhaust  of  the  smallest  machine. 


VACUUM   EXHAUST   PIPING. 


191 


Class  B7  — Vacuum  Exhaust  to  Cylinder  Relief  Valves.     The 

cylinder  reliefs  on  an  engine  are  frequently  left  open  to  the  atmos- 
phere to  show  when  they  are  "snifting."  The  actual  working 
service  of  this  valve  is  quite  insignificant,  since  it  is  very  sel- 
dom in  operation.  The  valve  is  placed  in  such  a  position  that 
it  will  relieve  the  cylinder  of  any  excessive  pressure  which 
may  be  caused  by  improper  valve  setting  or  by  excessive  com- 
pression. The  high-pressure  side  may  be  left  open  to  the  atmos- 
phere provided  the  engine  and  the  relief  valves  are  properly  set 


FIG.  157  (B7-i). 

and  do  not  show  any  leakage  that  may  cause  trouble.  Unless 
the  low-pressure  cylinder  relief  valves  are  kept  absolutely  tight, 
they  will  cause  considerable  trouble  on  account  of  the  air  which 
is  liable  to  leak  into  the  vacuum  lines.  To  avoid  this  difficulty, 
these  valves  are  frequently  piped  to  the  exhaust  from  the  low- 
pressure  cylinder. 

The  connections  shown  in  Fig.  157  (By-i)  will  work  up  very 
nicely,  using  flanged  relief  valves,  cast-iron  bodies,  pipe  bends, 
an  opening  in  the  bed  plate  for  the  pipe  to  pass  through,  and 
flanged  faces  on  the  exhaust  elbow  to  which  are  attached  the 
relief  pipes.  The  Corliss  valves  can  be  removed  without  inter- 
fering with  these. 

If  the  high-pressure  side  of  the  engine  is  to  have  reliefs  piped 
from  it,  the  piping  should  be  done  in  the  manner  illustrated  in 


IQ2  STEAM  POWER  PLANT  PIPING  SYSTEMS. 


157-  The  reliefs  should  discharge  into  the  high-pressure 
exhaust,  in  which  case  there  should  be  used  a  flanged  side- 
opening  return  bend,  as  shown  by  the  dotted  lines,  to  which  the 
pipe  bends  may  be  attached.  The  piped  relief  is  objectionable 
because  it  allows  the  relief  to  be  neglected  and  to  waste  steam  in 
the  most  expensive  manner.  Engine  builders  in  general  prefer  to 
have  the  valve  left  open,  their  reason  being  that  if  everything  is 
as  it  should  be,  the  valve  will  not  blow.  If  these  connections  are 
to  be  used,  the  engine  builder  should  be  required  to  furnish  them. 


CHAPTER   XII. 
ATMOSPHERIC    EXHAUST    PIPING. 

Class  Cl  and  2  —  Atmospheric  Exhaust ;  Main  and  Branches 
to  Engines.  The  exhaust  main  and  its  branches  which  connect 
the  exhaust  ports  of  the  engines  in  a  non-condensing  plant  with 
the  atmosphere  are  constructed  with  details  similar  to  those  of  a 
vacuum  exhaust  line.  The  various  parts  of  atmospheric  exhaust 
systems  may  be  made  sufficiently  tight  with  somewhat  less  effort 
than  is  necessary  for  condenser  connections.  In  atmospheric  ex- 
haust piping  spiral-riveted,  light-galvanized  iron  pipe  is  found  quite 
satisfactory.  If  the  pressure  on  the  exhaust  line  is  kept  at  about 
the  atmospheric  point,  the  light  valves  and  fittings,  sometimes 
called  the  "5o-lb.  standard,"  may  safely  be  used.  The  con- 
nections may  be  made  with  rubber- cloth  gaskets.  If  the  piping 
is  of  the  riveted  type  it  should  be  well  galvanized  after  the  flanges 
are  put  on.  This  galvanizing  serves  to  close  any  leaks  and  tends 
to  hold  the  joints  together  even  if  the  rivets  become  loosened. 
The  use  of  tarred  or  other  paper  in  joints  should  not  be 
sanctioned  on  account  of  the  bad  effects  that  may  be  caused  by 
oil  in  the  exhaust  steam.  The  tendency  of  boilermakers  to  make 
use  of  some  elastic  material  such  as  tarred  paper  in  riveted  seams 
apparently  shows  that  it  is  an  expensive  job  to  make  tight  seams 
in  piping  having  a  shell  but  one- eighth  or  three-sixteenths  in. 
thick.  The  use  of  thin  punched,  rolled  and  riveted  galvanized 
plates  should  be  avoided,  as  better  joints  can  be  made  with 
riveted  and  calked  black  plates.  If  the  main  is  sufficiently 
large  to  admit  of  the  use  of  a  quarter-inch  plate,  it  then  becomes 
a  simpler  matter  to  calk  the  black  plate  than  to  galvanize  it. 

For  small  pipes,  six  inches  or  less,  the  difference  in  cost  between 
light-weight,  commercial,  lap-welded  pipe  and  riveted  pipe  is  too 
small  to  be  worth  considering. 

For  a  very  high  grade  of  work  the  light  "casing"  or  tubing 
attached  to  the  flange  in  the  manner  shown  in  Fig.  158  (Ci-i) 
will  be  found  quite  satisfactory.  The  flange  as  shown  in  this 

193 


194 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


illustration  can  be  attached  in  the  field  and  the  light-welded 
pipe  may  have  a  maximum  diameter  of  30  in.  The  end  of  the 
pipe  should  project  slightly  beyond  the  face  of  the  flange  in 
order  that  the  joint  may  be  made  at  the  end  of  the  pipe.  The 
flange  should  be  shrunk  on  and  the  pipe  well  peened  into  the 
flange. 

There  is  another  style  of  connection  shown  in  Fig.  159 
(Ci-2)  which  makes  a  very  satisfactory  flange,  but  owing  to 
the  great  amount  of  "drawing  out"  of  the  metal  used  in  mak- 
ing the  flange,  the  connection  should  be  made  at  the  shop  where 


FIG.  158  (Ci-i). 


FIG.  159  (Ci-2). 


there  are  special  facilities  for  doing  this  work.  The  flanges 
used  in  this  joint  are  made  large  enough  to  be  loose  on  the  pipe 
and  serve  only  to  draw  the  flanged  ends  together.  In  Fig.  159 
the  flanges  are  made  of  cast  iron,  but  for  peened  work  as  in  Fig. 
158  the  flanges  should  be  made  of  wrought  iron,  rolled  steel,  or 
steel  casting.  For  light  casing  pipe  a  cheaper  form  of  con- 
struction is  found  in  the  use  of  fine  casing  thread-ends  and 
screwed  flanges. 

Atmospheric  exhaust  lines  up  to  24  in.  in  diameter  should  be 
made  of  metal  with  a  thickness  of  not  less  than  one  one-hundredth 
in.  per  inch  of  diameter.  Exhaust  lines  10  in.  in  diameter  have 
been  made  of  No.  20  galvanized  iron.  Since  the  exhaust  from  an 
engine  is  intermittent  and  the  pipe  a  condensing  body,  the 
vacuum  in  such  a  light  pipe  will  cause  it  to  collapse  even  though 
the  end  be  open  to  the  atmosphere.  An  atmospheric  line  should 
be  designed  as  if  it  carried  about  five  inches  of  vacuum.  Cast- 
iron  ells  and  tees  should  be  used  on  exhaust  lines  of  30  in.  and 
less,  but  for  larger  vacuum  exhaust  mains  the  ells  and  tees  can 
be  made  of  riveted  plates  with  the  flanges  placed  as  shown  in 
Fig.  159.  A  diameter  of  30  in.  is  virtually  the  dividing  point 


ATMOSPHERIC   EXHAUST  PIPING. 


195 


between  pipe-shop  and  boiler-shop  work.  Vacuum  exhaust 
mains  30  in.  or  less  in  diameter  can  be  made  of  welded  pipe  with 
screwed  flanges  and  cast  fittings.  If  the  size  is  larger  than  30  in. 
the  pipe  thickness  becomes  sufficient  to  make  good  calked  work 
possible.  Cast-iron  fittings  for  a  five-foot  line  would  be  extremely 
heavy  and  short-radius  bends  would  be  used  to  reduce  the 
weight. 

Fig.  160  (Ci~3)  shows  a  5  X  3  X  4-ft.  tee  made  up  of  plate 
metal  and  loose  cast-iron  flanges  as  shown  in  Fig.  159,  with  ten- 
sion or  compression  posts 
(marked  a)  to  strengthen  the 
flat  faces.  This  tee  as  shown 
has  turns  of  large  radius  and 
is  of  a  size  which  would  be 
quite  out  of  the  question  for 
a  cast  fitting.  There  are 
about  12  sq.  ft.  of  flat  face 
on  each  side  of  the  tee  which 
must  resist  the  atmospheric 
pressure  at  15  Ib.  per  sq.  in.  FlG  l6o  (Cl_3) 

This  is  a  total  of  about  26,000 

Ib.  pressure,  or  3,700  Ib.  for  each  of  the  seven  posts.  These  posts 
should  be  of  pipe  and  have  steel  flanges  at  the  ends  riveted  to 
the  shell. 

As  exhaust  lines  are  of  a  light  type  of  construction  it  is  neces- 
sary that  they  be  well  protected  against  water  pockets  and  water 
hammer.  The  drains  should  be  in  the  same  direction  as  the  flow 
of  the  steam  and  there  should  be  some  sort  of  a  water  seal  as 
shown  in  Fig.  161  (Ci-4).  In  Fig.  161  the  distance,  a,  should 
be  made  sufficiently  great  to  prevent  the  pulsating  pressure  from 
churning  the  water  out  of  the  seal.  While  the  gage  may  show 
but  little  back  pressure,  the  exhaust  may  still  be  blowing  through 
if  there  is  a  short  water  seal  at  a.  Twenty-seven  inches  of  still 
water  will  provide  an  effective  seal  against  a  back  pressure  of 
one  pound,  but  in  actual  practice  such  a  short  seal  will  not  be 
effective  if  the  engine  is  running.  To  have  the  seal  operative 
under  all  working  conditions,  the  distance,  a,  should  not  be  less 
than  five  or  six  feet.  The  casing  pipe  should  not  be  less  than 
four  inches  in  diameter,  and  a  loose  cap  should  cover  the  top  of 
the  well  to  facilitate  the  removal  of  the  drain  pipe.  The  drain  to 


1 96 


STEAM  POWER   PLANT  PIPING   SYSTEMS. 


the  sewer  should  be  left  open  so  that  an  operator  may,  by  inspec- 
tion, know  what  is  passing  away  through  the  drain. 

If  the  exhaust  pipe  is  not  less  than  three  feet  above  the  floor 
the  seal  may  be  made  of  elbows  and  valves  as  shown  in  Fig.  162 
(Ci~5).  In  case  of  a  considerable  back  pressure  with  this  arrange- 
ment of  piping  the  upper  portion  of  the  loop  may  be  used.  The 
closing  of  valve  a  will  make  the  loop  about  five  feet  high,  if  its  top 


FIG.  161  (Ci-4). 


FIG.  162  (Ci-s), 


is  placed  two  feet  above  the  bottom  of  the  exhaust  main.  By 
placing  a  check  valve  at  6,  the  surging  can  be  stopped  and  a 
shorter  seal  used. 

Class  C3  —  Atmospheric  Exhaust  to  Atmosphere.  The  atmos- 
pheric connection  from  non-condensing  engines  should  in  all 
cases  be  provided  with  a  sealed  drain,  and  an  exhaust  head  should 
also  be  provided  with  a  drain  and  a  short  seal.  For  condensing 
engines  the  atmospheric  pipe  may  be  run  to  the  atmosphere  without 
an  exhaust  head.  A  simple  form  of  exhaust  head  which  will  be 
found  more  serviceable  than  one  made  of  galvanized  iron  is  shown 
in  Fig.  163  (03-1).  This  form  is  suitable  for  use  on  condensing 


ATMOSPHERIC   EXHAUST   PIPING. 


I97 


work.  The  spiral,  <z,  throws  the  condensation  to  the  side  of  the 
pipe,  and  the  lip,  b,  overlaps  the  face  of  the  upper  portion  of  the 
head,  c.  This  allows  the  water  to  be  carried  into  the  annular 
recess,  d,  and  conducted  to  the  sewer  through  the  pipe,  e.  The 
entire  upper  portion  of  the  head  is  made  of  cast  iron  and  is  heavier 
and  more  durable  than  the  pipe  itself. 

Where  the  exhaust  and  drain  pipes  pass  through  the  building 
roof  there  should  be  provided  a  roof  sleeve  and  a,n  umbrella  which 
will  care  for  the  expansion  and  contraction  of  the  pipe  and  at  the 
same  time  will  prevent  leakage  at  the  roof.  Fig.  164  (03-2) 


FIG.  163  (Cs-i). 


FIG.  164  (C3-2). 


shows  a  roof  sleeve  made  of  heavy  galvanized  iron  with  a  thimble, 
a,  through  which  the  drain  from  the  exhaust  head  passes.  The 
diameter,  b,  of  the  roof  sleeve  should  be  made  large  enough  to  allow 
the  flange  at  the  end  of  the  pipe  to  be  passed  through.  The 
umbrella  should  be  made  in  two  pieces,  with  each  piece  attached 
to  a  half  clamp.  At  least  three  ply  paper  should  be  laid  on  the 
roof  and  the  roof  plate  of  the  sleeve  should  be  well  tacked  down 
upon  it.  After  erection,  the  roof  plate  should  be  mopped  and 
at  least  three  ply  paper  placed  over  it.  Such  gravel  as  is  used 
on  the  remainder  of  the  roof  should  then  be  placed  over  the  plate 
and  the  roof  cement  run  into  the  joint,  c}  and  up  the  side  of  the 


198  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

sleeve  to  protect  it  against  the  weather.  After  the  umbrella  has 
been  well  secured  to  the  pipe  the  joint,  </,  may  be  filled  with  lead 
to  prevent  leakage.  The  thimble,  a,  should  fit  the  pipe  closely  and 
what  little  leakage  occurs  at  the  joint  ordinarily  will  not  cause  any 
trouble.  If  necessary,  a  coupling  with  the  umbrella  soldered  to 
it  may  be  placed  immediately  above  the  sleeve  as  indicated  by  the 
dotted  lines.  Stays  such  as  are  shown  at  e  should  be  attached  to 
the  roof  sheathing  to  prevent  the  pipe  from  swaying  sideways  and 
damaging  the  light  roof  sleeve  or  umbrella.  There  should  be 
nothing  to  interfere  with  the  free  expansion  of  the  pipes  running 
through  the  roof,  and  if  the  building  is  very  high  the  umbrella 
should  be  made  with  a  deep  drop  flange  to  suit  the  amount  of 
travel  caused  by  expansion,  which  for  an  exhaust  line  varying  in 
temperature  from  32  degrees  to  212  degrees  would  be  about 
i %  in.  per  100  ft. 

Class  C4  —  Atmospheric  Exhaust ;  Auxiliary  Main.  In  a  con- 
densing plant  an  auxiliary  exhaust  main  should  be  used  for  the 
auxiliary  machinery.  Ordinarily  this  main  would  be  designed  to 
take  care  of  less  than  one-sixth  of  the  total  steam  generated.  Its 
area  would  be  about  one-sixth  of  that  of  all  the  exhaust  steam 
openings  including  those  of  the  auxiliaries.  Such  a  main  in  a 
plant  having  four  i,5oo-kw.  units  would  have  an  area  equal  to  that 
of  four  24-in.  main  exhausts  and  the  auxiliaries.  This  would  be 
about  2,000  sq.  in.  Since  one-sixth  of  this  area  is  333  sq.  in.  a 
20-in.  pipe  would  be  required.  If  most  of  the  larger  auxiliaries 
are  electrically  driven  the  exhaust  may  be  of  such  a  small  amount 
that  if  the  water  be  taken  from  the  hot-well  at  100  degrees  the 
exhaust  will  not  raise  its  temperature  higher  than  170  degrees. 
With  motor-driven  auxiliaries  but  one-fifteenth  of  the  steam 
generated  would  be  returned  to  the  heater,  and  the  cross-sectional 
area  of  the  pipe  would  need  to  be  but  one-fifteenth  of  2,000  sq.  in., 
or  133  sq.  in.  Thus  a  pipe  with  not  less  than  a  i4-in.  diameter 
would  be  required.  This  size  is  more  often  used  for  such  service. 

Since  the  auxiliary  exhaust  is  used  in  connection  with  auxiliary 
machines  and  will  have  small  branches,  it  may  be  found  more  eco- 
nomical to  use  standard  pipe,  screwed  flanges,  and  cast-iron  fittings 
throughout.  To  avoid  the  separate  handling  of  drips,  the  branches 
to  the  auxiliaries  should  enter  above  the  bottom  of  the  main,  and  the 
main  should  have  a  slight  pitch  towards  the  heater.  The  pitch, 
however,  is  not  absolutely  essential,  as  the  flow  of  steam  towards 


ATMOSPHERIC  EXHAUST  PIPING.  199 

the  heater  will  carry  the  drips  with  it.  It  is  often  difficult  to  make 
suitable  provision  for  an  auxiliary  exhaust  system,  and  therefore 
it  should  be  given  careful  consideration  before  floor  levels  and 
similar  details  are  determined  upon.  Care  should  be  taken  in 
designing  so  that  the  exhaust  will  drain  to  the  heater  and  the 
heater  be  placed  sufficiently  high  to  enable  the  water  to  flow  to 
the  feed  pump  suction  by  gravity. 

Class  C5  —  Atmospheric  Exhaust  5  Auxiliary  Main  to  Atmos- 
phere. As  it  will  be  necessary  when  cleaning  the  heater  to  dis- 
charge all  exhaust  steam  through  the  atmospheric  connection,  the 
atmospheric  connection  from  the  auxiliary  main  should  have  the 
same  capacity  as  the  main  itself.  The  amount  of  steam  wasted 
to  the  atmosphere  in  such  a  short  time  would  be  so  small  that  it 
would  neither  pay  to  install  a  reserve  heater  nor  make  any  double 
connections  to  allow  for  the  running  of  the  auxiliaries  under 
vacuum.  An  atmospheric  connection  also  serves  as  a  safety-valve 
line  on  the  exhaust  system  to  prevent  the  pressure  from  exceeding 
some  predetermined  amount.  The  type  of  valve  that  should  be 
used  in  an  atmospheric  connection  should  be  selected  for  such 
service  and  no  other.  In  fact,  if  there  is  more  steam  supplied  to 
the  heater  than  can  be  condensed,  a  back-pressure  valve  should  not 
have  a  seat,  but  should  serve  as  a  resistance  in  the  line,  maintaining 
a  fixed  pressure  and  allowing  the  excess  steam  to  waste  to  the 
atmosphere. 

Fig.  165  (05-1)  shows  a  good  form  of  noiseless  back-pressure 
valve.  The  piston  has  toothed  edges,  which  decrease  the  resist- 
ance to  the  flow  as  the  steam  is  admitted  through  the  port  opening. 
The  cushion,  a,  serves  to  lessen  the  jar  on  the  valve  when  the 
lever  drops.  There  are  no  seats  for  the  valve  to  pound  upon,  and 
since  the  piston  slides  its  action  is  noiseless.  Although  the  piston 
does  not  close  tightly  the  leakage  past  the  valve  is  very  slight. 
This  valve  is  well  suited  for  exhaust  systems  carrying  a  back 
pressure  and  in  which  the  quantity  of  exhaust  supplied  to  the 
neater  is  ordinarily  greater  than  can  be  condensed. 

For  a  heater  which  is  being  supplied  with  an  insufficient  amount 
of  steam  to  raise  the  temperature  of  the  water,  it  would  be  advis- 
able to  use  a  valve  of  this  form  with  seats  to  close  upon.  Such 
seating  faces  are  shown  by  the  dotted  lines  at  b.  This  type  of  valve 
will  close  sufficiently  tight  for  the  purpose  just  described.  Owing 
to  the  fact  that  the  valve  leaves  its  faces  when  steam  is  discharging 


200 


STEAM   POWER   PLANT  PIPING   SYSTEMS. 


through  the  serrated  portions  of  the  piston,  this  valve  will  be  free 
from  any  great  amount  of  pounding.  The  atmospheric  pipes 
should  be  provided  with  a  roof  sleeve  and  an  umbrella  similar  to 
those  used  for  the  pipes  from  the  engines.  The  drain  c  should  be 
piped  to  the  sewer,  as  it  is  not  possible  to  lead  the  drips  back 
through  the  valve  if  the  pressure  is  slightly  above  atmosphere. 
This  drain  may  connect  with  the  drain  from  the  exhaust  head. 


FIG.  165  (€5-1). 


FIG.  166  (C6-i). 


Class     C6  —  Atmospheric     Exhaust;     Branch     to     Heater.     If 

possible,  the  exhaust  branch  to  the  heater  should  drain  from  the 
exhaust  main  into  the  heater.  If  the  bottom  of  the  exhaust  main 
is  above  the  overflow  of  the  heater,  the  detail  shown  in  Fig.  166 
(C6-i )  will  take  care  of  the  drains  and  allow  steam  to  enter  at  the 
top.  This  will  be  a  desirable  arrangement  if  the  heater  is  able  to 
condense  all  of  the  steam  fed  to  it.  The  pipe  a  serves  a  double 
purpose,  as  it  allows  air  to  either  enter  or  be  discharged  from  the 
heater.  Since  the  arrangement  shown  in  Fig.  166  is  for  a  con- 
densing plant,  the  amount  of  water  sent  to  the  heater,  when  an  air 
pump  is  used,  would  ordinarily  maintain  a  vacuum  of  16  or  18  in. 
To  allow  the  water  to  flow  to  the  pump  suction  it  would  be  neces- 
sary to  raise  the  heater  i  ft.  for  each  inch  of  vacuum  carried.  If 
the  pipe  a  is  open,  any  increased  amount  of  steam  or  a  decreased 
amount  of  water  will  cause  the  air  to  be  partially  discharged  until 
the  condensing  surface  is  just  sufficient  to  condense  steam  at 
atmospheric  pressure.  As  soon  as  the  amount  of  water  is  increased 
or  the  amount  of  steam  diminished  the  air  will  rush  back  into  the 
heater.  The  line  a  automatically  cuts  the  condensing  surface 
in  or  out,  Instead  of  discharging  the  steam  through  the  atmos- 


ATMOSPHERIC   EXHAUST  PIPING. 


201 


pheric  valve  when  there  is  too  much  air  in  the  heater  the  air  alone 
is  discharged  from  the  heater  and  no  steam  is  wasted  in  the  process. 
If  the  exhaust  main  is  much  lower  than  the  heater  this  main  can 
be  drained  with  an  en  trainer  as  shown  in  Fig.  167  (C6-2).  This 
is  the  regular  method  of  draining  vacuum  mains  in  connection 
with  an  elevated  jet  condenser.  If  the  flow  of  exhaust  steam  is 
very  light  the  bleeder  a  may  be  left  open  to  the  sewer.  Instead 
of  placing  the  grease  extractor  at  the  heater  opening  as  indicated 
by  b,  it  would  be  advisable  to  locate  it  at  a  lower  point,  c,  and 
allow  the  grease  extractor  to  handle  both  the  entrained  oil  and 


FIG.  167  (€6-2). 


FIG.  168  (€6-3). 


water.  If  this  practice  is  followed  there  will  be  no  other  drain 
required.  The  exhaust  branch  connecting  the  separator  with  the 
heater  should  drain  either  to  the  heater  or  to  the  separator.  If 
the  auxiliaries  are  placed  close  to  the  heater  their  exhaust  should 
be  run  back  and  discharged  at  the  head  of  the  separator  as  shown 
in  Fig.  168  (06-3).  In  this  figure  the  grease  extractor  is  shown 
at  a.  The  exhaust  from  an  auxiliary  is  carried  by  the  pipe  b  to  the 
exhaust  main  c.  The  drain  from  the  grease  extractor  should  be 
run  to  the  sewer,  as  the  water  contains  too  much  grease  to  make 
it  advisable  to  return  it  to  the  boiler. 

Class  C7-17  —  Atmospheric  Exhaust  to  Pumps  and  Small 
Engines.  The  connection  shown  in  Fig.  169  (Cy-i)  is  consid- 
ered standard  for  all  the  auxiliary  machines  in  the  classes  from 
€7  to  C 1 7.  If  the  exhaust  main  is  2^  in.  or  more  in  diameter  it 
should  be  fitted  with  flanged  tees  even  though  the  side  outlets  are 
as  small  as  ij  in.  If  the  branches  are  2^  in.  or  larger  the  stop 


202 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


valve  should  be  flanged  and  connected  directly  to  the  tee,  using, 
if  desired,  a  screwed  drip  ell  at  the  bottom  with  the  flange  connected 
to  the  pump.  The  drains  for  the  exhaust  branches  should  be 
made  of  not  less  than  three-eighths-inch 
pipe.  The  connection  shown  in  Fig.  169 
allows  a  swing  in  both  a  vertical  and  hori- 
zontal plane.  If  the  auxiliary  branch  is 
made  of  4-in.  pipe  the  net  cost  of  a  4-in. 
flanged  angle  valve  would  approximate 
$6.35  and  the  combined  cost  of  a  4-in. 
flanged  elbow  and  gate  with  an  extra  joint, 
$8.10,  or  a  difference  in  favor  of  the  angle 
valve  of  $1.75. 

The  arrangement  of  the  exhaust  branches 
is  quite  simple.  First,  the  drain  should  be 
placed  at  the  lowest  portion  of  the  branch 
in  order  to  clear  the  branch  of  condensation 
when  starting  or  running  slowly;  second,  the  stop  valve  should 
be  placed  at  the  main  to  enable  the  branch  to  be  repaired  without 
interfering  with  the  main,  and  also  to  prevent  the  branch  from 
filling  with  condensation  when  shut  off;  third,  the  branch  should 
enter  the  main  above  the  bottom  and  preferably  at  the  top;  fourth, 


FIG.  169  (C;-i) 


FIG.  170  (07-2). 

long  branches  should  rise  to  their  highest  point  at  the  auxiliary 
and  should  then  be  given  a  pitch  for  the  remainder  of  the  dis- 
tance to  the  exhaust  main,  although  this  requirement  is  fre- 
quently a  difficult  one  to  fulfill. 

Fig.  170  (€7-2)  illustrates  a  long  branch  running  to  the  main 
in  the  most  approved  manner.  The  horizontal  connection  should 
have  a  slight  pitch  towards  the  main  in  order  to  avoid  pockets 
where  the  line  sags. 


ATMOSPHERIC  EXHAUST  PIPING. 


203 


Fig.  171  (07-3)  shows  a  line  with  a  considerable  pitch  which 
in  reality  is  an  " up-hill"  line  before  discharging  into  the  main. 
A  line  supported  in  such  a  manner  that  it  is  level  throughout  would 
serve  quite  as  well  and  would  make  the  pipe  fitting  a  much  simpler 


FIG.  171  (€7-3). 


FIG.  172  (€7-4). 

matter.  The  machinery  that  lies  in  basements,  etc.,  is  generally 
difficult  to  keep  properly  drained  without  resorting  to  drains  to 
the  sewer. 

Fig.  172  (07-4)  shows  such  a  line  as  has  just  been  mentioned 
with  sewer  drains  that  can  be  closed  as  soon  as  the  steam  unit  is  in 
operation.  To  reduce  the  length  of  the  "lift"  to  the  least  amount 
possible,  the  riser  a  should  be  placed  close  to  the  exhaust  main. 
The  line  b  should  have  a  fall  through  the  entire  distance  to  the 
entrainer  c.  These  entrainers  are  standard  articles,  being  listed 
by  the  manufacturers  as  a  "drainage  fitting,"  and  are  made  in 
different  sizes  of  from  2  to  8  in. 

Class  CIS  —  Atmospheric  Exhaust  to  Stoker  Operators.  The 
majority  of  stokers  are  operated  by  an  engine,  and  the  exhaust  in 


204 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


some  cases  being  fed  in  under  the  grates,  the  clinker  is  thereby 
broken  up  and  does  not  adhere  to  the  grates.  In  other  stokers 
it  is  required  that  the  exhaust  be  used  to  protect  the  castings  used 
in  connection  with  the  furnace.  The  stoker  steam  unit  should 
be  connected  to  the  exhaust  main  in  such  a  manner  that  its 
exhaust  can  be  delivered  to  the  exhaust  main  without  going  to 
the  furnace.  The  furnace  can  then  take  the  exhaust  from  the 
main  if  the  engine  is  not  running,  or  the  engine  can  discharge 
direct  to  the  furnace  if  it  is  necessary  to  shut  off  the  main. 


FIG.  173  (Ci8-i). 

This  can  all  be  provided  for  in  a  simple  manner  by  adopting 
the  design  shown  in  Fig.  173  (Ci8-i).  If  the  engine  sup- 
plies more  steam  than  the  stoker  requires  the  excess  flows  to 
the  exhaust  main.  If  the  engine  does  not  furnish  sufficient  steam 
the  extra  amount  will  flow  from  the  main.  The  branches  indi- 
cated by  a  should  always  be  the  low  connections,  otherwise  the 
low  line  will  accumulate  condensation  and  if  the  furnace  valve  is 
opened  to  a  considerable  extent,  this  condensation  will  then  be 
thrown  over  and  crack  the  hot  castings.  The  practice  of  work- 
ing the  small  amount  of  condensation  that  accumulates  in  the 
low  line  through  the  furnace  all  the  time  is  considered  safe,  but  it 
is  dangerous  to  pick  up  a  "pocket"  of  water  and  throw  it  upon 
the  hot  iron.  In  starting  up  the  engine  the  drain  b  should  be 
left  open  for  a  time. 


ATMOSPHERIC   EXHAUST   PIPING. 


205 


With  underfeed  stokers  the  exhaust  line  should  be  run  under 
the  floor  and  if  the  slide  valves  of  the  cylinders  are  located  at 
the  rams  the  exhaust  and  drips  can  be  led  to  any  exhaust  main 
that  may  lie  in  the  boiler  room  basement.  Unfortunately,  there 
are  few  installations  provided  with  basements  for  exhaust  mains 
and  the  piping  for  such  stokers  is  usually  one  of  the  crudest 
details  to  be  found  in  a  system  of  station  piping. 


FIG.  174  (Ci8-2). 

Fig.  174  (Ci8-2)  illustrates  the  older  method  of  reversing 
the  strokes  of  the  rams  with  the  reversing  valves  located  at  the 
ram  cylinders.  The  arrangement  shown  in  Fig.  175  (€18-3) 
is  laid  out  on  the  same  principle  as  the  older  form  with  the  dif- 
ference that  in  the  new  form  the  reversing  valves  are  located 
away  from  the  ram  cylinders  and  long  pipe  ports  are  used  from 
the  valve  to  the  cylinder.  The  reversing  valve  is  operated  by  a 
steam  pump  cylinder  with  its  time  regulation  governed  by  oil 
resistance.  The  port  opening  in  the  oil  by-pass  from  one  end  of 
the  cylinder  to  the  other  is  increased  or  decreased  by  means  of  a 
hand-operated  valve.  A  check  valve  is  placed  between  the  two 
ends  of  the  cylinder,  which  allows  an  unobstructed  passage  of  oil 
on  the  instroke  of  the  rams  and  forces  the  oil  through  the  resist- 
ance on  the  outstroke. 

The  design  shown  in  Fig.  174  requires  more  mechanism  to 
convey  motion  from  the  controller  to  the  cylinder  valves,  but  it 
reduces  the  port  length  to  but  a  few  inches.  The  steam  and  exhaust 
lines  in  this  older  style  of  controller  have  their  flows  always 


206 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


in  the  one  direction  and  the  drips  are  being  constantly  worked 
out  of  the  lines.  The  pressure  of  the  steam  in  those  lines  is 
always  maintained  and  is  not  wasted  to  the  atmosphere  at  each 
stroke  as  is  the  case  in  the  design  shown  in  Fig.  175.  This  latter 
form  possesses  the  advantage  of  being  free  from  levers,  rock 
shafts,  etc.,  and  thus  makes  a  cleaner  device  in  the  boiler  room. 
In  the  latter  arrangement  the  two  lines  to  the  cylinders  cannot 
be  drained  and  the  condensation  causes  much  snapping  and 
cracking  from  one  line  to  the  other.  This  makes  it  impossible 
properly  to  lubricate  the  ram  cylinders  and  increases  the  stresses 
and  wear  on  the  entire  stoker-operating  mechanism. 


FIG.  175  (€18-3). 

The  desirable  features  in  stoker-operating  machinery  include 
elimination  of  all  rock  shafts,  levers  and  similar  parts,  and  the 
maintenance  of  a  constant  pressure  and  direction  of  flow  in  the 
pipe  lines.  At  present  each  of  the  two  styles  just  described  com- 
plies with  one  requirement  and  fails  in  the  other.  A  desirable 
feature  which  neither  of  the  two  types  provides  is  that  the  ram 
shall  remain  in  until  the  controller  starts  it  for  another  charge. 
The  ram  should  then  make  the  outstroke  and  the  instroke  imme- 
diately following  each  other  and  then  remain  in  until  it  is  again 
started  by  the  controller.  If  this  method  is  followed  the  coal 


ATMOSPHERIC   EXHAUST  PIPING. 


207 


will  not  cake  around  the  mouth  of  the  bore  to  the  retort  and  thus 
prevent  the  ram  from  entering. 

These  are  more  in  the  nature  of  machine  than  piping  details, 
but  as  has  already  been  stated  many  other  details  must  be  con- 
sidered in  order  to  provide  a  good  piping  system.  The  piping, 
whether  it  has  the  arrangement  shown  in  Fig.  174  or  175,  should 
not  be  buried,  confined  or  subjected  to  the  corrosive  action  of 
cinders  and  water.  Such  piping  should  be  free  to  expand  and 
should  at  all  times  be  accessible  for  repairs.  The  stoker  con- 
tractor should  be  asked  to  furnish  the  lower  part  of  the  boiler 
front,  the  controller,  the  stand  to  carry  the  ram  cylinders,  and 
possibly  the  cast-iron  conduit  as  shown  in  Fig.  176  (Ci8~4). 


FIG.  176  (Ci8-4). 

All  these  details  should  be  furnished  completed  so  that  the  steam- 
fitters  can  place  the  pipe  work  and  the  masons  build  in  the  floor. 
If  there  is  a  basement  under  the  boiler  room  floor  the  stands 
only  would  be  required  as  the  piping  in  this  case  could  be  placed 
below  the  ceiling  of  the  basement. 

Class  C19  —  Atmospheric  Exhaust  to  Roof  Conductors.  In  a 
non-condensing  plant  where  steam  is  exhausted  to  the  atmos- 
phere it  is  advisable  to  warm  the  roof  conductors  with  exhaust 
instead  of  live  steam  as  a  large  quantity  of  the  exhaust  steam  is 
wasted  in  any  case.  However,  as  the  live  steam  has  sufficient 
pressure  and  if  there  is  a  partial  passage  through  the  conductor 
where  the  most  trouble  occurs,  it  will  be  found  that  live  steam 
can  be  more  readily  forced  to  the  roof. 

Class  C20  —  Atmospheric  Exhaust  to  Heating  Systems.  The 
many  details  of  heating  systems  will  not  be  considered  here  except 
as  they  form  a  part  of  the  power  station  equipment.  The  subject 
of  heating  is  one  of  considerable  importance  for  isolated  stations 
and  for  large  buildings.  In  an  exhaust  heating  system  the  return 


208  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

drips  are  in  some  cases  quite  sufficient  to  feed  the  boiler  and  in 
this  event  it  may  be  necessary  to  deliver  live  steam  to  the  exhaust 
system  in  order  to  maintain  the  desired  back  pressure.  In  this 
case  the  generating  and  auxiliary  machinery  should  be  run  non- 
condensing  with  a  back  pressure  on  the  exhaust.  In  fact  the 
heating  system  should  be  the  chief  duty  of  the  plant. 

A  power  station  is  not  often  designed  for  supplying  steam  to  a 
heating  system,  and  wherever  heat  is  taken  from  the  plant  for 
such  purposes  it  is  somewhat  difficult  to  provide  for,  as  the  amount 
of  heat  required  is  usually  comparatively  small.  If  a  2o-hp. 
boiler  were  provided  for  heating  a  given  plant  it  would  not  be 
considered  good  engineering  practice  to  allow  the  condensation  to 
go  to  the  sewer,  but  if  the  plant  had  a  2o,ooo-hp.  boiler  capacity 
the  same  amount  of  steam  and  drips  may  both  go  to  waste  and 
but  little  note  be  taken  of  it. 

The  heating  system,  together  with  the  heater  auxiliaries,  etc., 
should  be  connected  to  the  atmospheric  exhaust  system.  Heating 
system  requirements  cannot  be  determined  to  any  great  degree 
of  nicety.  There  will  be  a  constantly  varying  demand  for  exhaust 
steam,  and  since  the  supply  of  exhaust  steam  is  determined  by  the 
quantity  of  steam  used  to  generate  power  the  boiler  feed  water 
fed  through  the  economizers  may  vary  in  temperature  between 
125  and  210  degrees.  There  is  no  serious  objection  to  this  change 
in  feed  water  temperature,  nor  is  there  any  other  way  to  better  the 
economy.  For  a  condensing  plant  using  economizers  it  would  be 
quite  wasteful  and  unnecessary  to  deliver  live  steam  to  the  heater 
in  order  to  maintain  a  high  water  temperature. 

The  system  of  exhaust  steam  heating  which  is  being  considered 
may  be  operated  with  a  back  pressure  on  the  auxiliaries  or  a 
vacuum  return  system  on  the  heating  coils  and  radiators.  If  a 
vacuum  return  system  is  used,  the  air  should  be  allowed  to  enter 
and  be  discharged  from  the  heater  as  shown  in  Fig.  166.  If  the 
air  were  removed  from  the  heater  it  would  cause  a  vacuum  on  the 
heater  as  well  as  on  the  heating  system.  The  vacuum  pump 
for  a  heating  system  should  be  independent  of  the  other  station 
apparatus  in  order  that  it  may  be  shut  down  in  the  summer  and 
run  at  night  in  case  all  other  machines  were  shut  down.  The 
vacuum  pump  should  deliver  the  return  condensation  and  air 
to  the  exhaust  heater, .  allowing  the  air  to  "be  precipitated,  and 
leave  the  heater  through  the  vent. 


ATMOSPHERIC   EXHAUST  PIPING.  2OQ 

If  the  plant  is  provided  with  surface  condensers  and  but  a 
small  amount  of  steam  is  required  for  the  heating  system,  it  may 
be  found  simpler  to  return  the  air  and  drips  to  the  surface  con- 
densers as  shown  in  Fig.  177  (C20-i).  The  drips  should  all 
flow  to  the  drip  receiver  as  shown.  The  riser,  a,  should  be  as 
short  as  possible  and  of  small  diameter  in  order  to  insure  a  high 
velocity.  The  drain,  b,  should  be  given  a  slight  pitch  to  the 
condenser  and  can  be  of  a  larger  size  of  pipe  than  a,  since  high 
velocity  in  this  pipe  is  not  essential.  The  reducing  valve,  c,  is  in 
reality  a  safety  or  relief  valve  arranged  to  blow  off  its  absolute 
pressure  of  10  lb.,  the  results  obtained  being  practically  the  same 


FIG.  177  (€20-1). 

as  though  the  exhaust  were  under  a  3-lb.  back  pressure.  This 
3-lb.  vacuum  on  the  drains  would  lift  a  solid  drain  in  the  line  0,  a 
distance  of  about  6  ft.  If  the  drain  can  be  returned  as  shown 
by  the  dotted  line  d,  less  vacuum  will  be  required  on  the  drain 
system.  The  objection  found  in  draining  to  the  condensers  is 
that  much  difficulty  may  be  encountered  at  night  when  the  plant 
is  shut  down  and  the  drains  are  not  working.  If  the  plant  is  to 
be  shut  down  for  3  or  4  hours  at  night  during  severe  weather  it 
will  not  be  safe  to  stop  the  drains. 

Fig.  178  (020-2)  shows  a  back-pressure  exhaust  heating 
system  and  its  exhaust  lines.  With  the  heater  under  atmospheric 
pressure  the.  valve  a,  may  be  set  for  30  lb.  if  necessary,  as  the  heater 
is  not  subjected  to  the  back  pressure.  The  valve  b,  should  be  set 
for  about  one  pound.  If  the  drain  c,  could  be  pitched  to  the 
heater  as  shown,  the  back  pressure  could  be  quite  small;  but  if 
the  drain  lies  lower  than  the  heater  as  shown  at  d,  it  will  then  be 
necessary  to  increase  the  pressure  enough  to  raise  the  water  in 
the  riser,  e.  If  the  riser  ey  is  say  10  ft.  long  it  may  be  then  found 
necessary  to  run  the  back  pressure  up  to  6  or  8  lb.  Gages  should 


210 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


be  placed  on  the  exhaust  main  and  on  the  heater  to  show  the  set 
of  the  back-pressure  valves. 

The  system  shown  in  Fig.  178  requires  no  additional  apparatus, 
and  the  condenser  need  not  be  of  the  surface  type  nor  be  run  so  as 
to  remove  the  drips.  The  exciter  engine  would  in  all  probability 
be  run  to  supply  current  for  the  lighting  system,  even  though  the 


FIG.  178 


plant  were  otherwise  shut  down.  A  live-steam  connection  can 
otherwise  be  made  to  the  exhaust  main  and  used  when  there  is 
not  enough  exhaust  steam  to  maintain  the  necessary  pressure.  A 
reducing  valve  can  be  set  to  open  the  live-steam  connection  into 
the  exhaust  system  whenever  the  pressure  in  the  exhaust  main 
drops  to  3  Ib.  It  may  be  found  that  this  exhaust  system  can  be 
more  economically  operated  by  wasting  the  drips  to  the  sewer 
than  by  carrying  the  necessary  back  pressure  to  elevate  and  return 
the  drips  through  a  considerable  distance  to  the  heater.  With 
drip  returns  as  shown  in  Fig.  178  there  would  be  no  heat  lost  due 
to  wasting  condensation  nor  by  leaving  the  drain  valve  open  so 
the  steam  will  blow  through  to  the  atmosphere.  In  fact,  the 
capacity  of  the  heating  system  would  be  very  materially  increased 
by  using  the  returns  c  and  d.  The  steam  which  does  not  pass 
through  these  returns  to  the  heater  would  be  free  to  pass  through 
the  valve  a. 

The  arrangement  of  this  system  as  shown  with  the  heater  under 
lower  pressure  than  the  exhaust  system  makes  the  handling  of 
drips  possible  in  the  most  extreme  cases.  For  instance,  Fig.  179 
(€20-3)  may  illustrate  a  coil  for  car-shop  pits  with  the  drip 
main  on  a  higher  plane  than  the  bottom  of  the  coil.  But  very 
little  back  pressure  on  the  exhaust  main  would  be  required  to 
handle  the  drips.  If  the  riser  a  is  4  ft.  in  length  a  2-lb.  back 


ATMOSPHERIC   EXHAUST   PIPING. 


211 


pressure  would  be  required  to  raise  the  drips.  If  the  drips  are 
blown  to  the  sewer  in  starting  the  coil,  then  but  a  fractional  part 
of  a  pound  of  back  pressure  will  carry  the  condensation  along 
with  the  steam  in  the  form  of  vapor  if  the  drain  valve  be  left  open 
and  the  steam  be  allowed  to  flow  through  it  back  to  the  heater. 
If  the  riser  a  is  10  ft.  in  length  and  the  difference  in  pressure  of 
the  steam  supply  and  the  drip  main  is  but  i  lb.,  it  will  then  require 
4  ft.  of  steam  plus  2  ft.  of  water  in  the  form  of  vapor  to  equal  i  lb. 
of  back  pressure.  Since  the  steam  would  have  a  volume  1,600 
times  that  of  water  it  would  require  but  one-four-hundredth  of  the 
steam  necessary  for  heating  to  atomize  the  condensation,  and  by 


/////Y///' ''''/////// 
FIG.  179  (020-3). 


lightening  the  column  be  able  to  raise  the  condensation  10  ft.  in  a 
vapor  column  weighing  i  lb.  Since  the  heating  system  requires 
from  i  to  2  per  cent  of  the  total  steam  and  the  vaporizing  steam 
but  one-four-hundredth  of  the  amount,  it  will  be  noted  that  the 
steam  flow  through  the  drip  lines  will  be  an  insignificant  amount 
and  only  sufficient  to  raise  the  temperature  of  the  feed  water  a 
fraction  of  a  degree.  The  drips  can  then  be  left  well  open,  the 
drains  and  the  air  well  cared  for,  traps  or  vapors  rising  from  the 
sewers  avoided  and  no  heat  units  wasted.  This  system  is  especially 
suited  for  installations  requiring  other  feed  water  than  for  the 
heating  system  alone  and  where  all  the  exhaust  steam  is  condensed 
in  either  the  heating  system  or  the  heater. 

The  exhaust  line  to  the  heating  system  should  be  provided  with 
a  large  grease-extracting  separator  having  either  a  water  seal  or 
a  trap  in  the  discharge  to  the  sewer.  If  the  plant  is  run  non- 
condensing  and  the  exhaust  wasted  to  the  atmosphere,  then  such 
steam  as  would  be  blown  through  the  drip  system  would  cause 
waste  due  to  the  lost  energy  occasioned  by  the  back  pressure  on  such 
an  amount  as  was  used  to  remove  the  drips.  The  amount  so  used 


212 


STEAM  POWER   PLANT  PIPING   SYSTEMS. 


would  in  regular  practice  be  considerably  greater  than  that  required 
for  the  heating  system. 

The  system  shown  in  Fig.  180  (€20-4)  is  applicable  to  non- 
condensing  plants  such  as  isolated  stations,  etc.  The  auxiliaries 
have  one  exhaust  connection  to  the  heating  system  and  a  second 
exhaust  which  is  free  to  the  atmosphere.  The  valve  a  would  be 
set  with  say  a  o.25-lb.  back  pressure  and  the  valve  b  with  3  to 
5  lb.,  or  whatever  amount  is  necessary  to  return  the  drips.  The 
valve  c  is  placed  in  the  heater  connection  to  provide  for  an  exhaust 


*//£/?r/*e 


FIG.  180  (€20-4). 


to  the  atmosphere  if  the  heater  should  be  out  of  service.  By  using 
two  mains  as  shown  it  is  necessary  to  place  the  back  pressure  only 
on  such  machines  as  are  required  for  the  heating  systems. 

In  order  to  avoid  the  necessity  of  cutting  the  auxiliaries  in  or  out 
to  suit  the  demands  of  the  heating  system  the  atmospheric  valves 
may  be  placed  at  each  of  the  auxiliaries  as  shown  in  Fig.  181 
(020-5).  The  Valve  shown  in  detail  will  blow  open  to  the  atmos- 
phere when  the  back  pressure  in  the  heating  main  reaches  some 
set  amount,  say  5  lb.,  and  when  the  back  pressure  drops  to  say  3  lb. 
the  valve  will  close  to  the  atmosphere  and  discharge  steam  to  the 
heating  system.  The  valve  weight  should  be  in  the  position 
indicated  by  a  when  open  to  the  heating  main,  and  in  the  position 
b  when  open  to  the  atmosphere.  When  the  valve  starts  to  close 
or  open  it  takes  the  full  travel  without  stopping,  as  the  greatest 
change  in  pressure  available  is  required  to  start  the  valve  from 
either  position. 


ATMOSPHERIC   EXHAUST   PIPING. 


213 


With  the  heating  system  arranged  in  this  manner  some  machines 
can  be  set  to  throw  in  before  others,  and  the  last  machines  to  go  in 
on  the  heating  system  would  be  the  first  to  go  out  in  case  of  an 
increase  in  back  pressure.  The  machines  can  be  adjusted  to  throw 
in  at  any  desired  time  by  sliding  the  weight  pn  the  lever.  Ordi- 
narily, the  best  station  systems  are  those  which  can  easily  be  con- 


FIG.  181  (€20-5). 

trolled  by  hand  rather  than  those  which  are  dependent  upon 
automatic  devices.  A  simple  form  of  quick-reversing,  three-way 
valve,  if  applied  to  the  system  shown  in  Fig.  180  in  place  of  the  two 
valves  shown  in  the  auxiliary  exhaust,  would,  in  all  probability, 
provide  a  more  reliable  design  than  that  shown  in  Fig.  181,  and 
furthermore,  it  would  be  free  from  the  pound  of  the  automatic 
valve  shown  in  the  latter  figure.  This  automatic  valve  can,  how- 
ever, be  supplied  with  a  dash  pot  and  be  made  as  quick  and 
reliable  as  any  atmospheric  valve. 


CHAPTER    XIII. 
BOILER    FEED    MAINS    AND    BRANCHES. 

Class  Dl  and  2  —  Boiler  Feed  Mains  and  Branches  to  Boilers. 

Since  the  boiler  lines  in  a  plant  are  frequently  subjected  to  50  per 
cent  higher  pressure  than  exists  in  the  boilers,  the  feed  lines  should 
be  constructed  to  withstand  such  excess  pressures.  Pump  gover- 
nors and  relief  valves  will  in  time  reduce  the  pressure  to  the  amount 
set,  but  the  fact  should  not  be  overlooked  that  these  extreme  pres- 
sures are  a  part  of  the  ordinary  feed  line  performance.  This 
excessive  pressure  will  occur  occasionally  regardless  of  the  pre- 
cautions which  may  be  taken,  but  with  careful  attention  and  slow- 
speed  pumps  the  excess  can  be  reduced  to  a  minimum.  Relief 
valves  simply  aid  in  protecting  the  pumps  and  pipe  lines  and  do  not 
insure  the  maintenance  of  a  constant  pressure. 

A  pump,  when  operated  at  a  constant  speed  in  connection  with 
water  relief  valves,  will  give  the  following  results:  Reliefs  that 
start  to  discharge  or  leak  at  a  pressure  of  60  Ib.  discharge  but  little 
water  at  a  pressure  of  80  Ib.  When  water  passes  through  the 
reliefs  at  the  rate  of  15  ft.  per  second  the  pressure  runs  up  to  140  Ib. 
The  reliefs  discharge  a  certain  quantity  of  water  at  a  certain  pres- 
sure, and  to  discharge  a  greater  quantity  a  greater  pressure  is 
required.  In  order  to  prevent  a  constant  leakage  through  the 
reliefs  they  should  be  set  considerably  above  the  working  pressure, 
that  is,  if  the  working  pressure  is  160  Ib.  the  reliefs  should  be  set 
at  1 80  Ib.  If  such  leakage  is  not  stopped,  it  is  probable  that  the 
valves  will  be  ruined.  Much  of  the  trouble  from  excessive  pres- 
sure can  be  avoided  by  the  use  of  well-designed  relief  valves. 

In  the  relief  valve  shown  in  Fig.  182  (Di-i)  the  pilot  relief 
valve,  a,  is  used  to  admit  pressure  to  the  cylinder  under  the  pis- 
ton, thus  balancing  the  piston  and  allowing  the  valve,  c,  to  open. 
There  is  an  opening  through  the  stem,  6,  by  means  of  which  the 
same  pressure  is  maintained  above  the  piston  as  under  the  valve,  c. 
Since  the  hub  opening  at  /  is  made  fairly  tight,  the  pressure  in 
the  chamber,  d,  is  wasted  through  the  partially  opened  drain,  e. 

214 


BOILER   FEED    MAINS   AND    BRANCHES. 


215 


FIG.  182  (Di-i). 


The  leakage  can  occur  through  the  hub,  /,  only  at  such  times 
as  the  valve,  c,  is  open.  The  capacity  of  the  valve,  a,  should  be 
somewhat  greater  than  the  waste 
through  the  drain,  e,  in  order  to 
maintain  pressure  in  d.  The  drain, 
e,  should  not  be  discharged  into  the 
waste  pipe  from  the  valve,  c,  as  this 
pipe  is  under  pressure  due  to  the 
volume  of  water  which  passes  through 
it,  and  the  resulting  pressure  in  the 
space,  d,  would  cause  the  piston  to 
close  slowly.  Since  the  piston  acts 
as  a  dash  pot,  this  valve  cannot 
chatter  on  its  face.  If  very  hot 
water  is  used  the  piston  can  be 
made  of  composition  metal  fitted 
with  packing  rings.  The  valve  is 
guided  by  means  of  the  hub,  /,  and 

can  be  readily  reground  by  removing  the  upper  cylinder  and 
clamping  the  hub  piece  with  the  screws  which  attach  the  cylinder. 
The  pilot  relief  valve,  a,  should  be  of  a  sensitive  and  high- 
grade  type,  and  if  different  sizes  of  main  relief  valves  are 
used  in  the  same  plant  they  should  all  be  supplied  with  pilot 
valves  of  the  same  size.  A  spare  pilot  valve  should  be  provided 
for  substitution  in  case  it  is  desired  to  repair  one  in  use.  The 
valve,  a,  has  but  little  service  to  perform,  and  if  it  is  merely  off  its 
seat,  the  pressure  will  enter  the  chamber,  d,  allow  the  valve,  c, 
to  open  and  remain  open  during  the  time  the  valve,  a,  is  discharg- 
ing. When  the  valve,  a,  closes,  the  pressure  on  the  under  side  of 
the  piston  is  zero.  Then  if  it  is  assumed  that  the  pressure  on  the 
upper  side  of  the  piston  and  on  the  under  side  of  the  valve,  c,  is 
120  Ib.  with  the  pressure  above  the  valve  20  lb.,  and  if  the  piston 
has  twice  the  area  of  the  valve,  c,  or  the  area  of  the  valve  is  25 
sq.  in.  and  that  of  the  piston  50  sq.  in.,  there  would  then  be  a 
pressure  of  6,000  lb.  tending  to  close  the  valve  and  a  pressure  of 
2,500  lb.  tending  to  open  it.  This  is  a  net  pressure  of  3,500  lb. 
tending  to  close  the  valve.  When,  owing  to  the  opening  of  the 
valve,  a,  the  pressure  in  the  chamber,  d,  is  the  same  as  that  on 
the  upper  side  of  the  piston,  there  will  be  a  pressure  of  3,000  lb. 
exerted  in  opening  the  valve,  c.  When  the  valve,  a,  is  closed  and 


216 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


there  is  no  pressure  in  d,  there  will  be  a  pressure  of  3,000  Ib. 
exerted  toward  closing  the  valve,  c.  The  objectionable  feature  in 
the  type  of  valve  shown  in  Fig.  182  is  that  there  is  pressure  upon 
the  piston  at  all  times  and  therefore  a  tight  fit  must  be  main- 
tained in  order  to  avoid  excessive  leakage. 

The   valve    shown    in   Fig.    183    (Di-2)    has    a    loose-fitting 
piston,  the  clearance  affording  an  opening  for  the  waste  from  the 


FIG.  183  (Di-2>. 


FIG.  184  (Di-3). 


chamber,  a,  which  is  put  under  pressure  by  the  relief  valve,  b. 
The  chamber,  c,  is  always  open  to  the  atmosphere.  The  stem,  d, 
slides  loosely  in  the  sleeve.  The  drain,  e,  is  made  of  sufficient 
size  to  take  care  of  all  drips  past  the  piston  and  stem.  The 
capacity  of  the  valve,  fr,  should  be  made  greater  than  the  leak 
past  the  piston.  This  type  of  valve  is  readily  reground  and 
requires  no  close-fitting  or  tight  pistons.  The  valve  may  be 
placed  in  the  reverse  position  to  that  shown  in  the  illustration 
by  the  use  of  the  spring,  /,  which  has  sufficient  tension  to  sup- 
port the  valve. 

Another  type  of  relief  valve  is  shown  in  Fig.  184  (Di~3). 
This  valve  requires  pressure  in  the  chamber,  a,  in  order  to  decrease 
the  resistance  to  the  flow  of  water  at  the  valve.  The  piston  is 
open  to  the  atmosphere  and  the  small  leakage  passing  it  may  be 
piped  away.  This  valve  may  not  be  as  complete  a  relief  valve 
as  those  shown  in  Figs.  182  and  183,  but  its  simplicity  is  a  good 
feature. 


BOILER  FEED    MAINS   AND    BRANCHES.  2 1/ 

There  are  various  methods  employed  in  the  general  construc- 
tion of  feed  lines.  It  is  the  general  practice  to  use  iron  pipe 
for  cold-water  lines  carrying  water  at  a  temperature  of  less  than 
200  degrees  and  brass  pipe  for  high-temperature  lines  carrying 
water  at  a  temperature  above  200  degrees.  If  the  working  steam 
pressure  is  not  over  175  Ib.  full- weight  iron  pipe  is  frequently 
used.  Above  that  pressure  extra  heavy  iron  pipe  is  used.  The 
heavy  pipe  is  used,  not  because  the  lighter  pipe  will  not  stand 
the  pressure,  but  in  order  to  insure  longer  life. 

The  material  to  be  used  in  the  construction  of  feed  lines 
depends  largely  upon  the  water  to  be  handled.  If  low-temper- 
ature water  passes  through  the  mains  a  lighter  weight  iron  pipe 
may  safely  be  used,  since  with  low  temperature  there  will  be  no 
trouble  from  scale  or  pitting.  If  the  water  is  chemically  treated 
before  it  is  fed  to  the  boilers,  it  will  neither  scale  nor  pit  the  pipe, 
even  though  the  water  is  raised  to  a  high  temperature.  If  an 
open  heater  is  used  and  the  temperature  is  raised  to  the  boiling 
point,  or  212  degrees,  pitting  will  not  occur,  but  the  water  may 
deposit  scale.  The  smoother  the  interior  of  the  pipe  the  less 
trouble  there  will  be  from  scale.  If  it  is  known  that  the  water  tends 
to  scale  the  pipe  there  will  then  be  no  danger  of  its  pitting  or 
eating  the  pipe.  In  this  case  seamless-drawn  iron  tubes  may 
be  used  and  afford  a  smooth,  clean  main.  In  ordinary  practice, 
however,  screwed  iron  pipe  of  full  or  extra  heavy  weight  is  used. 

If  the  feed  water  contains  acids  which,  while  preventing  scale, 
eat  the  iron  pipe,  the  feed  main  should  be  made  of  seamless  brass 
tubing  one-eighth  inch  or  less  in  thickness.  It  is  not  practicable 
to  use  screwed  connections  with  light  brass  tubing.  Such  tubing 
is  expanded  into  cast-iron  flanges  with  a  tube  roller  and  the  end 
of  the  tube  turned  back  on  the  flange  as  shown  in  Fig.  185 
(Di-4).  To  prevent  the  flange  from  working  back  while  the  end 
of  the  tube  is  being  turned  over,  the  diameter  of  the  tube  is 
increased  at  the  point,  a,  back  of  the  flange. 

It  is  a  common  practice  to  make  feed-water  mains  and  branches 
of  brass  pipe  of  the  same  diameter  as  iron  pipe  which  would  serve 
the  same  purpose.  The  thickness  of  the  brass  pipe  should  be 
about  the  same  as  that  of  the  commercial-weight  steel  pipe  generally 
sold.  This  weight  of  pipe  should  not  be  understood  as  the  "full 
weight"  pipe  generally  found  in  pipe  tables.  Fittings  should  be 
of  flanged  cast  iron  regardless  of  what  material  the  pipe  is 


218 


STEAM   POWER   PLANT  PIPING  SYSTEMS. 


made.     Screwed  fittings  should  not  be  used  on  pipe  of  greater 
diameter  than  two  inches. 

A  very  satisfactory  arrangement  of  feed  mains,  since  they  are 
generally  three  inches  or  more  in  diameter,  is  to  use  brass  tubing  as 
shown  in  Fig.  185  and  make  the  boiler  branches,  which  may  be 
2  in.  or  less  in  diameter,  of  standard  threaded  brass  pipe.  If 
the  branches  are  2\  in.  in  diameter  and  are  flanged  throughout 


FIG.  185  (Di-4). 


FIG.  186  (Di-s). 


it  is  nevertheless  good  practice  to  make  them  of  brass  pipe  of  iron 
pipe  size,  because  it  is  less  expensive  to  use  pipe  than  to  bend 
tubing.  The  boiler  branches  usually  consist  of  numerous  small 
pieces  which  if  tubing  were  used  would  require  the  attaching 
of  a  large  number  of  flanges.  If  2-in.  branches  are  used  the 
valves  and  fittings  should  all  be  screwed. 

The  fittings,  such  as  elbows,  tees,  and  flanged  unions  should  be 
of  extra  heavy  cast  iron.  It  is  unnecessary  to  install  brass  fittings 
for  feed-water  service,  and  their  use  will  increase  the  cost  of  the 
piping  system.  If  fittings  of  brass  were  used  they  would  be  of  a 
lighter  pattern  than  cast-iron  fittings,  while  in  reality  they  should 
be  of  a  heavy  pattern  so  that  they  would  not  stretch  under  any 
ordinary  conditions  of  service.  It  is  better  for  a  fitting  to  break 
than  to  stretch,  because  if  a  fitting  is  broken  during  erection  a  new 
one  can  be  substituted  immediately,  but  if  a  fitting  is  strained  its 
joints  cannot  be  closed  without  excessive  tension  on  the  threads. 


BOILER  FEED   MAINS  AND   BRANCHES. 


Good  joints  are  easily  made  between  brass  pipe  and  iron  fittings, 
while  joints  of  brass  pipe  with  brass  fittings  are  difficult  to  make. 
When  two  metals  in  a  joint  are  united  with  the  threads  turning 
under  heavy  compression,  one  metal  should  be  hard  and  the  other 
soft.  If  they  are  of  the  same  degree  of  hardness  the  threads  of  one 
will  tend  to  destroy  those  of  the  other. 

In  the  general  design  of  a  feed-water  main  and  its  branches 
long-radius  bends  should  be  used  rather  than  short,  right-angle 
turns.  In  many  cases  it  will  be  found  possible  to  use  bends  instead 
of  elbows.  The  long-radius  bend  shown  in  Fig.  186  (Di-5)  is 
preferable  to  an  elbow  fitting  such  as  would  ordinarily  be  used 
close  to  the  boiler.  Such  bends  afford  more  pliable  connections 
which  will  better  withstand  expansion  strains,  and  since  they  also 
offer  less  resistance  the  regulation  of  the  flow  of  water  to  the  boiler 
will  be  better. 

The  ideal  method  of  securing  a  uniform  flow  of  feed  water  to  all 
boilers  would  be  to  make  the  connections  as  shown  in  Fig.  187 
(Di-6).  It  is  quite  certain,  however,  that  the  improvement  in 


FIG.  187  (Di-6).  ~-T 

operation  would  not  justify  the  additional  joints  and  parts  and  the 
attendant  increased  cost.  To  secure  results  that  will  compare 
favorably  with  those  obtained  with  the  arrangement  shown  in 
Fig.  187  it  is  necessary  to  make  the  main,  a,  in  .Fig.  186  of  a  size 
sufficient  to  enable  about  the  same  pressure  to  be  maintained 
throughout  its  entire  length.  It  is  not  necessary  to  run  a  large 
line  between  the  pump  and  the  first  boiler  branch  from  the  feed 
-main,  but  from  the  first  boiler  branch  to  the  last  one  the  pressure 
drop  should  be  kept  as  low  as  possible.  If  the  boilers  are  under 
175  Ib.  steam  pressure  and  the  feed  water  is  under  i8olb.  pressure 
at  the  first  boiler  connection  and  under  176  Ib.  pressure  at  the  last 
boiler,  then  the  available  water  pressure  at  'the  first  boiler  is  four 
times  that  at  the  last  boiler,  yet  there  is  but  a  4-lb.  drop  in  pressure. 
The  available  pressure,  which  is  the  difference  between  the  steam 


220 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


pressure  in  the  boiler  and  the  water  pressure  in  the  feed  main, 
should  be  kept  as  low  as  possible,  thus  permitting  the  line  to  operate 
with  the  feed  valves  well  open. 

The  arrangement  of  boiler  connections  shown  in  Fig.  188  (Di-y) 
would  probably  afford  nearly  uniform  pressure  at  the  differ- 
ent outlets  of  the  feed  main.  The  first  two  boilers  would  each 
have  a  wye  outlet  fitting  turned  as  shown,  so  as  to  offer  resistance 
to  the  flow  of  water  through  it,  the  resistance  increasing  with  the 
flow.  The  wyes  at  the  last  two  boilers  would  offer  the  least 
resistance,  and  by  using  standard  tees  at  the  two  center  boilers 
the  resistance  at  this  point  would  be  intermediate  to  that  of  the  two 
boilers  on  either  side. 


I  I 

II  II 

J1    \ 

FIG.  188  (Dr-7). 

It  will  be  noted  in  Fig.  186  that  the  feed-regulating  valve  is 
located  at  the  top  of  the  boiler.  To  avoid  lowering  the  branch  to 
a  point  which  may  be  reached  by  the  operators  and  then  raising 
it  to  the  top  of  the  boiler,  the  valve  is  operated  with  an  extension 
stem. 

The  feed  branches  should  be  made  as  short  as  possible  and  at  the 
same  time  should  have  sufficient  length  to  allow  for  free  expansion 
and  contraction.  With  most  installations  of  six  or  eight  boilers 
this  result  can  be  obtained  with  about  8  or  10  ft.  of  boiler  branch. 

Fig.  189  (Di-8)  shows  a  simple  feed  branch  arrangement 
for  a  double  system  of  feeding.  The  regular  feed  main  has  its 
operators  carried  down  and  placed  close  to  the  front  of  the  boiler 
setting.  The  auxiliary  feed  operators  at  the  rear  setting  are  used 
only  in  case  of  emergency;  the  inconvenience  found  in  operating 
them  in  this  manner  is  too  slight  to  require  any  more  expensive 
arrangement.  It  will  be  noted  that  Figs.  186  and  189  show 
branches  taken  from  the  tops  of  the  feed  mains.  This  arrangement 
is  advisable  wherever  possible,  as  it  affords  a  ready  means  of  dis- 
charging any  air  from  the  main  that  may  be  delivered  by  the 
pump.  It  will  also  be  noted  that  there  are  two  stop  valves,  a  check 


BOILER  FEED   MAINS  AND   BRANCHES. 


221 


and  a  regulating  valve,  for  each  branch.  This  arrangement  per- 
mits the  opening  of  the  check  valve  at  any  time  by  closing  the  two 
stop  valves.  The  feed-regulating  valve  should  not  be  regarded  as 
a  shut-off  valve,  as  the  nature  of  its  service  is  such  as  to  prevent  its 
remaining  in  a  condition  to  close  tightly.  The  independent  stop 
valves  are  necessary  to  admit  of  quick  repairs  to  the  feed  valve. 
The  stop  valves  should  be  of  the  gate  pattern  and  the  regulating 
valve  of  the  globe  or  angle  pattern. 

It  will  be  noted  in  the  designs  shown  in  Figs.  186  and  189  that 
the  regulating  valves  are  turned  with  their  stuffing  boxes  down- 


FIG.  189  (Di-8). 

ward.  This  arrangement  would  be  objectionable  if  used  on  the 
steam  connection,  since  it  permits  condensation  to  leak  through 
the  stuffing  boxes.  Valves  used  on  water  connections  are  as  liable 
to  leak  at  the  stuffing  boxes  in  one  position  as  another.  The 
objection  to  placing  water  valves  with  the  stuffing  boxes  downward 
is  that  the  heavier  particles  carried  with  the  water  will  lodge  in  the 
bonnet  of  the  valve  and  in  valves  of  the  gate  pattern  will  prevent 
them  from  opening  fully.  This  objection  is  not  as  marked  with 
valves  of  the  globe  and  angle  patterns  because  the  space  that  the 
valve  disk  opens  into  is  in  the  path  of  the  water  flow  and  therefore 
no  great  amount  of  deposit  can  collect.  This  method  is  demon- 
strated by  the  many  similar  valves  successfully  operated  in  the 
reversed  position. 


222 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


In  Fig.  190  (Di-9)  is  shown  a  detachable  feed-regulating 
and  check  valve  made  up  as  a  unit.  Since  the  joints  between  the 
valve  and  the  flange  are  ground,  the  valve  may  be  removed  by 
simply  loosening  the  nuts.  This  arrangement  allows  a  valve  to  be 


FIG.  190 


removed  for  repairs  and  a  spare  one  quickly  substituted  without 
shutting  down  the  boiler.  Feed  water,  should  enter  the  boiler  at  a 
point  considerably  below  the  water  line  in  order  to  prevent  any 
portion  of  the  feed  branch  from  filling  with  steam,  which  would 
cause  water  hammer  when  the  feed  valve  is  again  opened.  In 


FIG.  191  (Di-io). 

order  to  minimize  the  expansion  and  contraction  strains  it  is  advis- 
able not  to  allow  the  feed  water  to  come  in  contact  with  the  boiler 
until  it  has  been  heated  to  the  temperature  of  the  water  in  the  boiler. 
Fig.  191  (Di-io)  shows  a  feed-water  tube  arranged  to  dis- 
charge into  the  coldest  part  of  the  boiler.  The  nozzle  attached  to 
the  drum  has  a  blind  flange  which  closes  the  end  opening.  The 
feed  opening  is  at  the  side  of  the  nozzle.  As  this  tube  is  the  same 


BOILER  FEED   MAINS  AND   BRANCHES. 


223 


size  as  the  boiler  tubes  it  may  be  cleared  of  scale  at  the  same  time. 
As  feed  pipes  quickly  fill  with  scale  they  should  not  be  run  into 
the  boiler  without  providing  ample  means  for  cleaning. 

In  considering  the  details  of  feed-regulating  valves  it  should  be 
borne  in  mind  that  such  valves  are  at  all  times  but  partly  open. 
The  valve  disk  of  a  globe  valve  is  held  firmly  when  the  valve  is 
entirely  open  or  shut  and  therefore  will  not  chatter.  The  steam 
throttle  is  not  subjected  to  as  severe  service  as  a  feed-water  valve, 
since  steam  is  elastic  and  passes  the  throttle  at  a  constant  speed. 
The  feed  water  on  the  other  hand  passes  the  regulating  valve  inter- 
mittently, in  unison  with  the  pulsations  of  the  pump,  and  is  there- 
fore constantly  rocking  the  loose  disk  on  the  valve  stem.  A  disk 
held  as  shown  in  Fig.  192  (Di-n)  will  remain  stationary  on  the 
stem,  as  it  is  held  rigid  by  the  spring  above  it.  The  swing  check 
valve,  having  a  flat-faced  disk,  opens  and  closes  more  quickly  than 
the  poppet  type,  and  though  the  swing  type  may  not  be  quite  as 
tight  while  new,  it  is  more  suitable  for  a  boiler-feed  check,  since  it 
retains  a  good  face  and  guide  much  longer  than  the  other  type. 


FIG.  192  (Di-u). 


FIG.  193  (Di-i2). 


A  regulating  valve  is  seldom  operated  directly  by  the  hand  wheel, 
since  the  location  of  the  valve  is  such  as  to  invariably  require  an 
extension  stem.  In  Fig.  193  (Di-i2)  is  shown  a  valve  hand 
wheel  with  an  extension  fork  and  a  hand  wheel  for  the  extension. 
The  rod  is  of  pipe  pinned  as  shown,  and  the  hand  wheel  on  the 
regulating  valve  has  openings  in  the  rim  to  receive  the  operator 
fork.  If  the  hand  wheel  is  not  provided  with  holes  the  ends  of  the 
fork  may  be  run  through  between  the  arms  of  the  hand  wheel, 
which  is  the  usual  form  of  construction  for  valve  extensions. 

There  are  a  number  of  forms  of  automatic  feed  controllers 
designed  to  shut  off  the  feed  when  the  water  in  the  boiler  is  high 
and  to  open  it  when  the  water  is  low.  Some  are  operated  by  floats 
and  others  by  thermostats.  The  earlier  form  consisted  of  a  float 


224 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


attached  to  a  lever  valve  placed  inside  the  boiler,  the  construction 
being  very  similar  to  that  of  a  tank  float  valve.  To  overcome  the 
objection  to  placing  the  device  in  such  an  inaccessible  position  the 
float  was  placed  in  an  independent  water  column  with  a  shaft 
passing  through  the  stuffing  box  and  operating  the  balanced  feed 


FIG.  194  (Di-i3). 

valve  as  shown  in  Fig.  194  (Di-i3).  An  objection  to  this 
device  is  that  hollow  floats  are  very  uncertain,  and  to  operate  a 
regulating  valve  against  the  friction  of  two  stuffing  boxes  would 
require  a  float  of  considerable  size.  The  available  power  is  very 
slight,  and  it  requires  almost  constant  adjustment  to  keep  the 
regulator  in  continuous  operation.  To  overcome  the  difficulty 


FIG.  195  (Di-i4>. 

encountered  with  large  floats  and  the  lack  of  available  power  the 
float  is  made  small  and  without  the  stuffing  box.  Connection  is 
made  to  a  pressure  feed  valve  as  shown  in  Fig.  195  (Di-i4). 
This  device  has  a  further  advantage  in  the  location  of  the  feed  valve. 
This  can  be  operated  without  regard  to  the  position  of  the  float, 
since  the  connection,  a,  is  run  from  the  float  to  the  valve.  The 
waste,  b,  is  open  a  sufficient  amount  at  all  times  to  relieve  the 


BOILER  FEED   MAINS  AND   BRANCHES. 


22$ 


pressure  over  the  diaphragm  when  the  small  float  valve,  c,  is  closed 
and  thus  allows  the  feed  valve  to  open. 

To  overcome  the  fluctuating  movement  of  the  float,  float  valve, 
and  feed  valve  caused  by  the  constantly  varying  feed-water  level, 
which  variation  occurs  in  any  boiler  worked  approximately  at  its 
rating,  the  float  chamber  has  been  made  with  but  the  one  connection 
as  shown  in  Fig.  196  (Di-i5).  This  connection  is  placed  at  the 
low-water  level,  and  when  the  water  in  the  boiler  reaches  this  point 


FIG.  196  (Di-is). 

the  float  chamber  empties  its  water  back  into  the  boiler.  The 
float  chamber  then  fills  with  steam  and  the  float  drops.  When  the 
water  in  the  boiler  rises  and  covers  the  connection  the  steam  in  the 
float  chamber  condenses,  draws  the  water  in  and  raises  the  float, 
thereby  closing  the  feed  valve. 


FIG.  197  (Di-i6). 

It  will  be  observed  that  a  hollow  float  is  used  with  the  vari- 
ous types  of  feed  regulators  and  that  it  is  located  inside  a  part 
of  the  boiler  under  pressure  where  it  can  neither  be  observed 
nor  adjusted.  To  avoid  the  use  of  the  float-controller  regula- 
tor the  expansion-tube  type  has  been  introduced.  One  of  the 
earlier  forms  was  direct  connected  to  the  feed  valve  as  shown 


226  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

in  Fig.  197  (Di-i6).  The  brass  tube  is  given  a  slight  pitch 
(about  2  in.)  and  the  compression  bar,  a,  is  made  adjustable  in 
length  to  allow  for  the  closing  of  the  feed  valve  when  the  water  is 
at  the  desired  elevation.  The  air  cock,  b,  is  placed  in  the  steam 
branch  in  order  to  keep  air  out.  As  the  regulator  is  dependent 
upon  extreme  temperatures  it  is  necessary  that  the  water  in  the 
brass  pipe  be  as  cool  as  possible  and  that  the  steam  be  of  a  high 
temperature.  If  air  is  allowed  to  accumulate  in  the  steam  tubes 
it  will  eventually  reach  the  brass  tube  and  by  radiation  cause  the 
tube  to  drop  in  temperature  to  that  of  the  water;  therefore  it 
will  be  unable  to  raise  the  feed  valve  and  admit  water  to  the 
boiler.  The  regulator  shown  in  Fig.  197  and  other  direct-con- 
nected types,  including  Fig.  194,  are  defective  because  the  valve 
disk  is  ordinarily  held  just  off  its  seat.  With  the  valve  just  raised 
from  its  seat  and  the  pressure  in  the  feed-water  main  enough 
higher  than  the  boiler  pressure  to  allow  a  sufficient  quantity  of 
feed  water  to  pass  the  valve,  this  difference  in  pressure  soon 
causes  a  grooving  of  the  valve  and  an  increased  inability  to  close 
tightly. 

The  most  successful  regulating  devices  are  those  which  use  a 
pressure-operated  feed  valve  as  shown  in  Fig.  195.  This  same 
method  is  sometimes  employed  with  a  thermostat  controller,  the 


FIG.  198 


thermostat  operating  a  small  valve  that  admits  pressure  to  the 
feed  valve.  In  Fig.  198  (Di-i7)  is  shown  a  thermostat  con- 
troller of  this  type,  and  it  will  be  noted  that  the  mechanism  is 
entirely  external.  The  expansion  of  the  brass  tube  is  opposed  on 
one  side  by  a  rod  which  causes  the  end  of  the  tube  to  rise  and 
lower  in  accordance  with  its  varying  length.  The  pipe,  a,  to 
the  feed  valve  is  very  small  and  the  waste  valve,  b,  is  set  to  waste 
the  water  away  by  drops.  The  valve,  c,  is  constructed  to  with- 


BOILER  FEED   MAINS  AND    BRANCHES.  22? 

stand  a  considerable  wire-drawing  through  it.  The  details  of 
this  valve  are  shown  in  Fig.  199  (Di-i8).  In  many  respects 
this  type  of  regulator  is  free  from  the  uncertain  working  parts 
contained  in  all  the  other  forms  here  shown.  The  parts  are 
sufficiently  heavy  to  be  handled  safely  by  the  attendants  ordi- 
narily employed  in  boiler  rooms,  which  is  not  the  case  with  some 
of  the  delicate  thermostat  arrangements  that  are  attached  to 
water  columns.  Automatic  devices  in  a  steam  plant  must  with- 
stand not  only  the  severe  use  of  regular  operation,  but  also  the 
abuse  of  the  attendant.  It  is  also  necessary  that  a  regulator  be 
so  designed  that  if  the  boiler  should  become  cold  or  the  dia- 
phragm in  the  feed  valve  break,  the  feed  valve  will  immediately 
assume  the  open  position  and  flood  the  boiler  rather  than  close 
and  endanger  life  and  property  by  running  the  boiler  with  low 
water.  The  arrangement  shown  in  Fig.  198  provides  for  these 
conditions  in  a  satisfactory  manner. 

Thermometers  should  be  placed  in  the  boiler  feed  mains  at 
points  where  water  enters  and  leaves  the  heater,  where  water 
leaves  the  economizer,  and  also  at  least  one  at  the  point  where 
the  water  enters  the  boiler  farthest  from  the  economizer  or  heater. 
It  will  not  be  found  satisfactory  to  permanently  locate  thermom- 
eters at  these  different  points,  but  provision  should  be  made  for 
holding  a  thermometer  tube  at  any  of  them  so  that  the  tubes 
may  easily  be  interchanged  and  accurate  temperature  readings 
obtained. 

An  inexpensive  method  for  obtaining  accurate  temperature 
readings  is  to  place  mercury  pots  fitted  with  caps  that  may  be 
screwed  on  by  hand  at  the  different  points  where  temperatures 
are  taken,  as  is  shown  in  Fig.  200  (01-19).  The  openings 
for  the  thermometers  should  be  tapped  in  a  tee  or  ell  where  there 
is  a  considerable  thickness  of  metal  and  where  the  area  is  greater 
than  that  of  the  pipe.  This  will  avoid  reducing  the  cross  section 
of  the  pipe  and  impeding  the  flow.  To  hold  the  mercury  there 
should  be  inserted  in  the  hole  a  o.25-in.  steel  nipple  with  a 
thread  at  its  upper  end  long  enough  to  allow  a  cap  to  be  screwed 
over  it.  The  lo*wer  cap  and  the  bushing  should  be  of  brass, 
the  bush  being  0.25  to  0.5  in.  These  dimensions  will  permit  the 
lower  cap  to  pass  through  the  tapped  opening.  The  use  of  the 
small  nipple  requires  but  a  small  amount  of  mercury  to  cover 
the  thermometer  bulb.  The  mercury  standing  in  the  well  will 


228 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


have  the  same  temperature  as  the  water  in  the  pipe,  and  read- 
ings can  be  taken  soon  after  placing  the  thermometer. 

If  the  thermometer  is  to  remain  in  place  a  more  suitable 
arrangement  is  as  shown  in  Fig.  201  (Di-2o).  The  ther- 
mometer here  shown  is  of  standard  design.  It  has  a  metal  case 
which  is  attached  to  the  well  with  a  knurled  union,  by  and  its 


FIG.  199  (Di-i8).        FIG.  200  (Di-ip).        FIG.  201  (Di-2o). 

bulb  is  in  the  tube,  a.  There  should  be  as  many  wells  as  there 
are  points  where  the  temperatures  are  to  be  taken,  and  a  little 
oil  should  be  placed  in  the  well  before  inserting  the  thermom- 
eter. A  cap  is  furnished  with  each  well  to  protect  it  from  dirt 
and  damage  to  the  thread. 

Class  D3  —  Boiler  Feed  Branches  from  Pumps.  Each  branch 
from  a  boiler  feed  pump  should  be  provided  with  a  stop  valve  of 
the  gate  pattern  so  that  the  pumps  can  be  shut  off  from  the  main. 
Between  this  valve  and  the  pump  there  should  be  a  check 
valve  and  a  pressure  relief  valve.  It  is  possible  to  operate  the 
pump  without  any  one  of  the  three  valves,  but  if  the  safety  of  the 
pump  is  to  be  considered,  the  relief  valve  is  necessary.  To 
insure  the  continuous  operation  of  the  pump  it  is  necessary  to  use 
an  outside  check  valve.  A  swing  check  will  be  found  most  satis- 
factory for  this  service. 

Instead  of  introducing  a  tee  for  the  relief  valve  the  detail  shown 


BOILER  FEED   MAINS  AND   BRANCHES. 


229 


in  Fig.  202  (03-1)  will  be  found  more  compact  and  more 
economical.  The  pressure  from  the  pump  is  free  to  pass  the 
check  valve,  the  relief  in  this  position  protecting  the  pump  quite 
as  fully  as  though  it  were  directly  on  it.  The  relief  valve  should 
be  about  one-half  the  size  of  the  discharge  pipe.  The  outlet 
should  be  left  open  to  the  atmosphere  to  show  when  it  is  dis- 
charging, so  that  an  operator  will  be  more  careful  to  avoid  over- 
pressure in  the  line  or  pump  when  by  discharging  over  the  floor 
it  leaves  unmistakable  evidence  of  his  carelessness.  The  relief 
should  not  be  placed  between  the  pump  stop  valve  and  the  feed 
main  with  the  idea  of  protecting  the  main.  The  relief  valve 
should  protect  the  pump,  as  it  is  not  an  unusual  oversight  for  an 
operator  to  start  a  pump  with  the  discharge  valve  closed.  It  is 
quite  useless  to  place  the  relief  valve  on  the  feed  main,  as  there 
is  nothing  to  cause  excess  pressure  between  the  pump  and  the 
boiler  valves  unless  there  should  be  an  increase  in  the  temper- 
ature and  the  volume  of  water  confined  between  these  valves. 


-nV>-i'4Y'>-T^?T''Jjr  ~* 

1     1     1     1     1 

i    I         i    1    1    1 

1 

''., 

U5UJL  f1£TH00 

+-G/9S£Z 

'''.,, 

Of  F££0  f/?O/7            L~  ~J 

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—  —  y^  •  —  Ht^"'^  *^*  ^v  j*  r_t- 

FIG.  202  (03-1). 


FIG.  203  (D4-i). 


If  a  closed  heater  or  economizer  is  used  there  should  be  a 
relief  valve  placed  between  the  inlet  and  outlet  water  valves 
which  would  protect  the  heater  should  heat  be  turned  on  when 
the  valves  are  closed.  If  the  relief  valves  are  placed  in  this  man- 
ner there  is  then  no  necessity  for  placing  a  relief  valve  on  the 
main  itself.  If  the  pumps  are  provided  with  suitable  relief 
valves  the  relief  valve  for  the  heater  or  economizer  may  be  made 
small.  The  relief  valves  used  on'  the  heater  and  economizer 
serve  to  relieve  the  pressure  due  to  expansion  and  need  not  be 
over  three-fourths  in.  in  size. 


230 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


Class  D4  —  Boiler  Feed  to  and  from  Economizers.  The  reg- 
ular method  of  feeding  water  to  and  taking  it  from  an  econo- 
mizer is  to  introduce  the  water  at  the  bottom  and  discharge  it 
from  the  top,  with  the  flow  of  the  water  in  a  direction  opposite 
to  that  of  the  gases.  If  the  installation  is  of  such  a  nature  as 
to  make  it  necessary  both  to  receive  and  to  discharge  the  water  at 
the  top,  the  upper  manifold  may  be  blanked  so  that  the  water 
will  not  take  a  direct  path  from  the  inlet  to  the  outlet. 

In  the  arrangement  shown  in  Fig.  203  (04-1 )  a  solid  disk  of 
thin  copper  is  placed  between  the  two  gaskets  in  the  upper  sec- 
tions of  the  manifold.  The  water  takes  a  downward  course  in 
the  first  two  sections  and  is  delivered  to  the  lower  manifold, 
which  in  turn  delivers  the  water  to  the  bottoms  of  all  of  the 
remaining  sections.  It  will  be  noted  that  in  all  but  two  of  the 
sections  the  hottest  water  is  at  the  top,  and  since  the  hottest  gases 
also  lie  at  the  top  there  is  no  extreme  difference  of  temperatures 
which  will  induce  a  circulation  of  water.  The  water  passes 
slowly  and  freely,  always  moving  in  the  one  direction.  With 

such  a  path  water  from  the 
first  section  may  be  of  low 
temperature  while  the  water  in 
the  outgoing  sections  is  quite 
hot. 

The  usual  method  of  feed- 
ing by  which  the  water  enters 
the  bottom  of  the  economizer 
is  shown  by  the  dotted  lines  in 
Fig.  203.  With  this  arrange- 
ment, if  the  pump  is  fitted 
with  a  governor,  since  the 
bulk  of  the  water  flows 
through  the  lower  manifold 
which  is  not  exposed  to  the 
high-temperature  gases,  there 
is  less  danger  of  the  cold  in- 


i  OU  TL£T 

BLOCK  ASBESTOS 


FIG.  204  (D4-2). 


coming  water  cracking  the  tubes  when  the  economizer  is  blown 
off.  In  Fig.  203  the  lower  manifold  is  below  the  lower  headers. 
This  detail  should  be  avoided  wherever  possible.  The  gaskets 
are  difficult  to  place,  and  if  renewals  are  necessary  such  repairs 
must  be  made  in  an  inconvenient  place. 


BOILER   FEED    MAINS   AND    BRANCHES.  2$l 

The  detail  shown  in  Fig.  204  (04-2)  should  be  used  even 
though  it  is  more  expensive.  The  objectionable  manifold  below 
is  shown  in  dotted  lines  at  a.  To  permit  the  ready  removal  of 
a  damaged  section  one  wall  should  be  of  asbestos-lined  sheet 
metal.  The  top  of  the  economizer  should  be  covered  with 
asbestos,  and  means  should  be  provided  for  attaching  chain 
blocks  over  the  economizer  sections  to  facilitate  their  removal. 
It  will  be  noted  that  all  gaskets  shown  in  Fig.  204  are  open  to 
inspection  even  while  in  operation.  In  case  of  a  slight  leak  the 
joints  can  be  followed  up  without  interfering  with  regular  oper- 
ation. 

Class  D5  and  6  —  Boiler  Feed  Branches  to  and  from  Closed 
Exhaust  and  Vacuum  Heaters.  The  exhaust  closed  heater  and 
the  closed  heater  that  may  be  used  in  the  line  of  the  vacuum 
exhaust  should  be  provided  with  relief  valves  as  previously  stated. 
Where  there  is  an  abundance  of  exhaust  steam  there  is  no  per- 
ceptible saving  in  heat  units  by  the  use  of  an  open  exhaust 
heater  and,  with  a  closed  heater,  since  the  feed  water  is  kept 
separate  from  the  exhaust,  the  difficulty  of  eliminating  cylinder 
oil  from  the  exhaust  is  overcome.  U-shaped  copper  tubes  are 
not  subject  to  expansion  strains  and  therefore  are  suited  for  this 
class  of  heaters. 

There  are  two  distinct  types  of  closed  heaters,  the  steam- 
tube  and  the  water-tube  types.  Fig.  205  (D5~i)  shows  the 
water-tube  type  and  Fig.  206  (05-2)  the  steam-tube  type. 
The  form  shown  in  Fig.  206  has  been  used  more  extensively 
than  the  water-tube  type  notwithstanding  the  fact  that  the 
area  for  the  exhaust  is  much  more  restricted  than  in  the  water- 
tube  type,  which  is  a  condition  that  would  make  the  heater 
somewhat  more  efficient  at  the  expense  of  engine  economy.  The 
heating  surfaces  of  the  tubes  in  the  steam-tube  type  are  very 
efficient,  due  to  the  rapid  flow  of  steam  through  the  tubes  and 
the  complete  removal  of  the  air  that  may  be  contained  therein. 
The  outside  casing,  a,  of  the  steam-tube  type  of  heater  is  subjected 
to  the  full  boiler  pressure  and  is  exposed  to  the  eating  action 
of  the  water.  If  the  feed  water  contains  a  large  amount  of  car- 
bonate of  lime  or  magnesia,  considerable  scale  will  form  in  the 
heater.  In  the  form  shown  in  Fig.  206  it  is  easier  to  remove 
scale  from  the  outside  of  the  tubes  than  from  the  inside. 

The  closed  heater  is  superior  to  the  open  heater  only  because 


232 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


cylinder  oil  in  the  exhaust  steam  is  kept  out  of  the  feed  water.  If 
the  water  used  tends  to  form  scale,  the  open  type  of  heater,  with 
ample  space  for  accumulating  scale,  should  be  used.  The  oil 
should  be  removed  with  a  grease  extractor.  The  closed  heaters 
have  small  hand-hole  plates  for  removing  the  deposits  in  them, 
and  by  the  use  of  a  large  amount  of  chemical  with  the  heater  shut 


WATER 


FIG.  205 


FIG.  206  (05-2). 


off  from  the  system  it  is  in  some  cases  possible  to  loosen  the  scale 
sufficiently  to  allow  it  to  be  washed  out  through  the  hand-hole 
openings.  In  steam-tube  heaters  the  water  should  be  fed  to  the 
heater  at  a  low  point  and  taken  from  the  heater  at  a  high  point, 
with  a  blow-off  at  the  extreme  top  of  the  heater  to  remove  floating 
impurities.  The  feed  branches  should  be  by-passed  so  that  the 
heater  can  be  shut  off  and  the  feed  go  directly  to  the  boilers.  A 
thermometer  cup  should  be  placed  between  the  stop  valves  and 
the  heater  as  indicated  at  b  in  Fig.  206,  so  that  it  can  be  repaired 
when  the  heater  is  shut  off.  There  should  be  no  stop  valve  placed 
between  the  small  relief,  c,  and  the  heater.  It  is  preferable  to 
place  the  relief,  c,  directly  on  the  heater  to  lessen  the  possibilities 
of  impurities  blocking  the  connecting  pipe. 

Class   D7  —  Boiler  Feed;   Branches  to  and   from  Live   Steam 
Purifier.    The  usual  method  of  installing  a  live  steam  purifier  is  to 


BOILER  FEED   MAINS   AND    BRANCHES. 


233 


place  it  at  a  sufficient  elevation  above  the  boilers  so  that  it  will  feed 
by  gravity.  This  arrangement  is  shown  in  Fig.  207  (Dy-i). 
The  purifier  is  maintained  under  full  boiler  pressure.  The  pump 
delivers  water  to  the  scale-collecting  pans  at  the  top  of  the  purifier, 
after  which  the  water  overflows  from  one  pan  to  another  and  is 
finally  discharged  into  the  bottom  of  the  purifier.  By  virtue  of  the 
head,  0,  the  water  is  delivered  from  the  purifier  to  the  boilers.  This 
head  must  be  greater,  measured  in  pounds  per  square  inch,  than 


FIG.  207  (Dy-i). 


the  combined  losses  of  the  steam  through  the  steam  pipe,  b,  the 
water  line  to  the  feed  main,  c,  the  feed  main,  d,  and  the  branches,  e. 
These  losses  will  include  friction  through  the  pipe  fittings,  check 
and  feed  valves,  and  the  filter,  /,  should  a  filter  be  installed  in 
the  purifier.  There  is  another  loss  that  may  interfere  with  the 
feeding  of  some  one  boiler  in  the  battery.  This  loss  would  be  due 
to  that  particular  boiler  being  crowded  much  harder  than  the  others, 
while  they  were  taking  water  and  carrying  as  much  higher  pressure 
as  the  resistance  of  the  steam  line  would  amount  to.  If  there  is 
head  room  it  will  lessen  the  cost  of  installing  the  purifier  to  make 
the  head,  a,  about  eight  feet  and  use  ordinary  sizes  of  feed  main 
branches,  etc. 

There  are  two  methods  of  delivering  water  to  the  purifier,  one 
as  shown  in  the  illustration  with  a  float  to"  control  the  steam  to  the 
pump.  This  arrangement  is  especially  suited  for  a  plant  with  but 
one  purifier.  If  there  are  a  number  of  purifiers,  each  supplying 
one  or  two  boilers,  it  is  necessary  to  connect  the  float  with  the 
water-admission  valve  shown  by  the  dotted  lines  at  g  and  use  a 
pressure-controlling  pump  governor  shown  by  the  dotted  lines  at  h. 
In  this  case  the  pump  will  maintain  a  set  pressure  in  the  purifier 


234  STEAM   POWER   PLANT  PIPING  SYSTEMS. 

feed  main  and  each  purifier  will  take  water  independent  of  the 
others.  The  goose  neck,  /,  in  the  discharge  to  the  purifier  is  used 
for  the  purpose  of  sealing  the  water  line  and  preventing  it  from 
draining  into  the  purifier.  Such  draining  would  cause  serious 
water  hammer  when  the  water  started  feeding  again,  and  steam 
would  also  mingle  with  the  water  in  the  pipe.  A  purifier  is  one  of 
the  station  appliances  the  use  of  which  may  cause  more  or  less 
trouble,  but  if  properly  installed  it  can  be  operated  with  very  little 
attention.  In  cases  where  the  feed  water  carries  a  considerable 
amount  of  sulphates  a  purifier  will  aid  materially  in  keeping  the 
boilers  clean,  and  is  the  only  means,  aside  from  chemical  treatment, 
that  will  remove  the  sulphates  before  the  water  reaches  the  boilers. 

Class  D8  —  Boiler  Feed ;  Branches  to  and  from  Injectors.  Injec- 
tors are  so  little  used  in  the  large  power  plants  that  they  seldom 
enter  into  station  plans  or  systems.  It  has  become  quite  a  general 
practice  to  install  two  feed  pumps  even  in  small  plants.  The  only 
advantage  offered  in  the  use  of  an  injector  in  power  plants  is  the 
means  afforded  for  feeding  warm  water  when  for  any  reason  the 
heater  may  be  out  of  service.  Feeding  boilers  with  cold  water 
may  cause  damage  much  in  excess  of  the  cost  of  an  injector  and 
its  use  is  therefore  safer  practice.  The  injector  may  be  connected 
with  the  same  suction,  discharge,  and  steam  lines  as  the  pump, 
using  a  stop  valve  for  each  of  the  three  branches. 

Class  D9  —  Boiler  Feed ;  Branches  to  and  from  Meters.  As  a 
rule,  meters  in  power  plants  are  used  only  for  testing  purposes. 
Meters  should  be  installed  in  by-passes,  and  if  a  separate  meter  is 
used  for  each  boiler  the  most  direct  connection  through  the  meter 
should  be  used,  as  the  meter  itself  offers  obstruction  to  the  flow  of 
water.  This  arrangement  is,  however,  open  to  the  objection  that 
the  meter  by-pass  is  in  use  the  greater  part  of  the  time,  and  any 
added  friction  would  tend  to  become  a  regular  operating  loss. 
When  some  of  the  boilers  in  service  are  operated  with  meters  and 
the  others  are  not,  it  would  then  be  necessary,  in  order  to  control 
the  feed,  to  close  the  feed-regulating  valve  almost  tight  upon  its 
seat  and  hold  back  the  feed,  which  service  is  severe  upon  the 
regulating  valve.  Instead  of  placing  a  separate  meter  on  each 
boiler  branch,  one  meter  fitted  with  a  by-pass,  flanges,  etc.,  can  be 
used  on  all  the  boilers,  all  boiler  branches  having  exactly  similar 
straight  sections  flanged  at  each  end  so  that  they  can  be  removed 
and  replaced  by  the  meter. 


BOILER  FEED   MAINS  AND    BRANCHES.  23$ 

Fig.  208  (Dg-i)  shows  a  meter  arranged  in  the  manner  just 
described  and  also  the  removable  straight  section.  The  hangers 
which  support  the  ends  of  the  pipe  when  the  removable  section 
is  out  are  shown  and  also  other  hangers  which  support  the  meter 
and  enable  a  ready  connection  of  the  flanges.  The  section  can  be 
removed  and  the  meter  in- 
stalled while  the  boiler  is  in 


T  &G 

operation,    as   the   connection 

requires  but  a  few  minutes  to 

make.     An  advantage  in  using 

the  same  meter  for  the  different 

boilers  is  that  the  readings  will 

be  relatively  the  same  and  an 

exact  comparison  of  the  per-  FIG.  208  (09-1). 

formance     of     the     different 

boilers  can  be  had.     With  different  meters  on  the  different  boilers 

one  may  read  in  excess  of  the  exact  quantity,  since  all  mechanically 

registering  meters  are  inaccurate  to  a  greater  or  less  extent. 

Another  method  of  measuring  the  water  to  boilers  was  described 
in  a  previous  chapter  under  the  head  of  "  Boiler  Feed  System." 
In  this  method  one  large  meter  is  placed  between  the  auxiliary 
feed  and  the  regulating  feed  main  and  the  water  allowed  to  flow 
through  the  meter  to  the  auxiliary  mains  for  such  boilers  as  are 
to  be  tested.  The  boilers  have  separate  feed  branches  to  each 
main.  The  most  objectionable  feature  found  in  such  a  system 
is  that  a  meter  of  sufficient  size  to  accurately  record  the  water 
flow  for  a  large  number  of  boilers  is  inaccurate  when  used  with 
a  small  flow  through  it,  as  would  be  the  case  if  a  test  were  made  on 
but  one  boiler.  Another  disadvantage  is  found  in  the  use  of  many 
valves  which  open  into  other  boilers  and  lines  and  which  in  case 
of  leaks  would  permit  water  to  pass  the  meter  and  go  elsewhere 
than  into  the  boiler  that  was  being  tested. 

If  the  feed  branch  to  the  boilers  is  inaccessibly  located  the 
detachable  boiler  meter  can  be  located  in  the  by-pass  and  placed 
close  to  the  floor  with  two  wheels  mounted  on  an  axle  screwed  into 
a  tee  as  shown  in  Fig.  209  (Dg-2).  In  order  that  the  meter 
may  fit  the  different  locations  the  distance,  a,  should  be  maintained 
either  when  placing  the  branches  to  the  boilers  or  when  putting 
down  the  floor.  With  this  arrangement  one  man  can  roll  the  meter 
to  the  desired  boiler  and  place  the  by-pass  between  the  removable 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


section  and  the  boiler  wall.  When  he  is  ready  to  remove  the 
straight  section,  b,  the  meter  connection  may  easily  be  swung 
into  place. 

Class  DIG  —  Boiler  Feed;  Branches  to  Hot  Water  Plumbing 
Fixtures.  Ordinarily,  the  water  fed  to  the  boilers  is  sufficiently 
hot  for  lavatory  use.  It  is  not  gcod  practise  to  take  water  from 
the  feed  mains  for  any  other  purpose  than  for  boiler  feeding,  but 


2#J^32%^%2^^ 

FIG.  209  (Dg-2). 

as  the  amount  used  in  a  lavatory  is  small  it  is  better  to  take  the 
water  from  the  feed  mains  rather  than  provide  a  steam  heater. 
If  the  line  from  the  feed  main  to  the  lavatory  is  very  long  it  should 
be  of  three-eighths  or  one-half  inch  pipe,  covered  to  reduce  the 
water  loss  occasioned  by  wasting  cold  water  at  the  faucet  when 
warm  water  is  desired. 

There  are  two  distinct  methods  of  supplying  water  at  the  wash 
basins  or  sinks.  One  is  to  carry  it  under  full  boiler  pressure  to 
the  point  where  it  is  wanted,  using  a  standard  high-pressure  valve 
in  place  of  the  ordinary  plumbing  fixtures.  The  other  method 
is  to  lower  the  pressure  to  say  20  Ib.  by  means  of  a  reducing  valve 


BOILER  FEED  MAINS  AND   BRANCHES. 


237 


and  use  standard  plumbing  fixtures.  This  latter  method  is  liable 
to  cause  considerable  trouble,  especially  if  the  water  is  from  an 
economizer  at  a  temperature  higher  than  the  steam  for  the  pres- 
sure of  which  the  reducing  valve  is  set. 

The  use  of  the  reducing  valve  is  not  alone  sufficient  to  protect 
the  plumbing  fixtures  from  overpressure,  since  all  reducing  valves 
will  allow  the  pressure  past  the  valve  to  increase  by  reason  of  the 
leakage  when  the  flow  is  slight.  With  water  a  very  small  amount 
of  leakage,  possibly  half  a  pint, 
will  raise  the  pressure  of  the 
water  on  the  low-pressure  side 
to  that  on  the  high-pressure 
side.  In  order  to  protect  the 
plumbing  fixtures  it  is  necessary 
to  use  a  relief  valve  on  the  side 
that  has  become  reduced  in 
pressure  in  order  to  waste 
water  when  the  pressure  in- 
creases. Such  service,  however, 
is  very  severe  on  both  the  reduc- 
ing valve  and  the  relief  valve, 

since  the  leakage  past  the  valve  faces  will  soon  cut  them  out,  allow- 
ing the  leakage  cost  to  run  into  an  appreciable  amount. 

A  much  simpler  method  is  to  use  extra  heavy  materials  through- 
out and  avoid  complicating  the  operation  by  the  use  of  low-pressure 
plumbing  fixtures.  A  very  satisfactory  detail  for  this  work  is 
to  make  both  hot  and  cold  faucets  of  extremely  heavy  angle  valves 
with  brass  hand  wheels  and  a  small  polished  brass  sleeve  under 
the  valve  as  shown  in  Fig.  210  (Dio-i).  Fixtures  fitted  in  this 
manner  are  free  from  the  continuous  troubles  that  the  reducing 
valves  and  reliefs  always  develop. 


FIG.  210  (Dio-i). 


CHAPTER   XIV. 
AUXILIARY    BOILER    FEED    MAINS    AND    BRANCHES. 

Class  El  —  Auxiliary  Boiler  Feed  Mains.  The  line  used  as  an 
auxiliary  feed  for  the  boilers  is  often  designated  as  a  feed  main, 
though  in  reality  it  is  a  general  service  main  having  boiler  connec- 
tions that  enable  its  use  as  a  feed  main  when  desired.  The  regular 
duties  which  this  main  performs  include  the  following:  Low-pres- 
sure hose  service  for  wetting  ashes,  washing  floors,  etc.,  filling 
boilers  through  its  feed  branch  after  cleaning,  boiler  washing,  water 
supply  for  turbine  tube  cleaners,  and  fire  protection  service  in  the 
boiler  room.  The  method  of  connecting  the  auxiliary  boiler  feed 
main  has  been  shown  in  an  earlier  chapter  on  feed  mains. 

Since  it  may  be  called  upon  to  perform  the  same  duties,  the 
construction  of  the  auxiliary  main  should  be  as  thorough  as  that 
of  the  boiler  feed  main,  but  as  such  duties  would  be  infrequent 
smaller  pipe  may  be  used.  The  difficulties  encountered  in  feeding 
the  boilers  through  small  mains  would  occur  for  such  short  periods 
of  time  that  saving  in  the  cost  of  piping  should  determine  the 
relative  sizes  of  the  boiler  feed  main  and  the  auxiliary  main.  For 
the  same  reason  the  auxiliary  main  should  not  be  covered,  as  the 
saving  in  heat  during  the  short  use  of  the  piping  for  boiler 
feeding  purposes  will  not  warrant  the  original  outlay  for  heat 
insulation. 

No  boiler  plant  should  be  installed  without  an  auxiliary  boiler 
feed  main,  as  its  uses  aside  from  boiler  feeding  are  important  ones, 
and  water  for  them  should  not  be  supplied  from  the  boiler  feed 
main. 

Class  E2  —  Auxiliary  Boiler  Feed ;  Branch  to  Boilers.  In  Fig. 
189  (Di-8)  was  shown  a  satisfactory  connection  between  the 
boiler  and  the  auxiliary  feed  main.  The  two  mains  were  shown 
side  by  side  on  the  same  supports.  These  supports  also  were 
designed  for  carrying  a  plank  runway. 

Another  method  of  connecting  the  auxiliary  feed  main  to  the 
boiler  is  shown  in  Fig.  211  (£2-1).  The  single  feed  valve 

238 


AUXILIARY   BOILER  PEED   MAINS  AND   BRANCHES.      239 


FIG.  211  (Ea-i). 


with  its  extension  stem,  check  and  boiler  stop  valve  serves  both 

mains.     If   the   feed   and   check   valves   are   installed   as   earlier 

shown  in  Fig.  190   (Di-g)  this  connection  will  not  be  a  cause  of 

trouble,  but  with  feed  and  check  valves  screw-connected  into  the 

feed  branch  it  would  not  be  safe  to  attempt  repairing  them  unless 

the  boiler  were  shut  down.      With  the  double  set  of  feed  and 

check  valves,  as  shown  in  Fig.  189,  it  would  be  but  a  few  minutes' 

work  to  put  the  auxiliary  main  into 

service  so  that  the  boiler  could  be  fed 

through  its  auxiliary  feed  and  check 

valves,  thus  allowing  the  repairs  to  be 

postponed    until   a   convenient    time. 

The  presence  of  twice  as  many  feed 

and  check  valves  does  not  signify  that 

any    extravagant     outlay    has     been 

made,    as    the    operator   will    always 

have  in  reserve  "good  valves"  in  the 

auxiliary  main,  and  thus  he  will  be  able  to  transfer  the  valves  in 

good  condition  to  the  regular  main  and  use  the  old  valves  in  the 

auxiliary  main  when  they  become  badly  worn. 

Class  E3  —  Auxiliary  Boiler  Feed;  Branch  from  Pumps. 
Ordinarily  it  is  the  best  practice  to  use  two  feed  pumps  for  boiler- 
roon?  service.  These  pumps  should  be  of  the  same  pattern  and 
size  and  specially  designed  for  boiler  feeding.  Their  discharges 
should  connect  into  a  single  main  with  a  valve  between  the  pumps, 
one  end  of  the  main  connecting  with  the  regular  feed  main  and  the 
other  end  with  the  auxiliary  main.  By  placing  a  valve  in  the 
auxiliary  main  it  is  then  possible  to  use  either  one  of  the  pumps  for 
feeding  purposes  or  each  can  be  separately  used,  one  furnishing 
water  for  boiler  feeding  and  the  other  for  tube  cleaning,  boiler 
filling,  or  any  similar  service. 

If  fire  service  of  a  limited  amount  be  required  the  auxiliary 
main  may  be  used  for  such  purpose,  this  main  then  being  fed  by  one 
of  the  regular  feed  pumps.  If,  however,  the  buildings  and  plant 
are  to  be  insured  it  will  be  desirable  to  install  a  standard  pattern 
underwriters'  fire  pump  with  such  a  capacity  as  the  insurance 
board  may  direct.  Before  deciding  upon  the  use  and  purchase  of 
the  reserve  feed  pump  the  insurance  details  should  be  studied 
and  advice  sought  from  the  underwriters  as  to  what  capacity  of 
pump  they  will  insist  upon  having  installed.  The  underwriters' 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


pumps  are  made  to  conform  to  their  standard  specifications  and 
are  designed  to  carry  150  Ib.  pressure.  Some  of  the  makes 
recommended  will  barely  comply  with  the  specifications,  and 
others  are  generously  designed  so  that  they  will  carry  far  greater 
pressures,  supply  a  larger  quantity  of  water,  and  are  in  every  way 
better  able  to  withstand  service. 

If  the  fire  pump  is  also  to  serve  as  a  reserve  feed  pump  it  should 
be  one  of  the  better  makes.  A  ready  means  of  roughly  determining 
this  point  is  by  asking  the  bidders  for  the  pump  contracts  what 
weight  of  pump  they  propose  to  furnish.  For  fire  protection  it  is 
best  to  have  the  fire  pump  in  continual  easy  service,  as  this  practice 
assures  that  the  pump  will  always  be  in  operating  condition  should 
it  be  suddenly  called  upon  for  fire  duty.  This  class  of  daily 
service  is  approved  by  the  insurance  companies,  and  in  fact  they 
approve  of  using  pumps  with  high  and  low  pressure  steam  ends 
that  will  serve  for  all  ordinary  uses,  such  pumps  being  supplied 
with  a  quick-throw  valve  that  will  change  both  cylinders  into 
high-pressure  ones  for  fire  service. 

Class  E4  —  Auxiliary  Boiler  Feed  to  Hydraulic  Tube-Cleaner. 
The  branch  from  the  auxiliary  main  which  supplies  water  to 
hydraulic  tube-cleaners  should  be  taken  off  at  a  convenient  point 
for  attaching  the  hose.  A  gate  stop  valve  should  be  placed  at  the 


^^^^ 

FIG.  212  (£4-1). 

main  and  means  provided  for  attaching  a  valve  at  the  end  of  the 
branch,  this  valve  being  shifted  with  the  hose  from  one  cleaner 
branch  to  another.  The  operating  valve  must  be  located  so  that 
it  can  be  reached  from  the  platform  used  when  cleaning  boilers. 
Fig.  212  (£4-1)  shows  such  a  branch  when  provided  with  a 


AUXILIARY  BOILER  FEED   MAINS  AND   BRANCHES.      241 

quick-operating  valve,  A,  a  rigid  hanger,  B,  to  relieve  the  strains 
due  to  shifting  the  hose,  and  a  stop  valve,  C,  that  is  left  open  when 
the  valve,  A ,  has  been  attached. 

A  usual  type  of  construction  for  the  valve,  A ,  is  to  bolt  a  flat  bar 
to  the  hand  wheel  of  an  angle  valve  having  a  handle  secured  to  the 
end  of  the  bar  and  thus  making  a  crank  with  increased  leverage  for 
opening  and  closing  the  valve. 

The  platform  shown  in  Fig.  212  is  ordinarily  constructed  of 
wooden  horses  supporting  planking;  in  fact,  it  is  common  practice 


FIG.  213  (£4-2). 

to  use  such  a  platform  in  the  larger  plants  which  have  many  boilers 
and  which  are  designed  with  every  detail  in  masonry  and  metal 
carefully  planned.  Such  a  platform  is  a  crude,  unsightly  device, 
almost  continuously  in  use  and  conspicuously  in  view.  In  a  plant 
having  twelve  5oo-h.p.  boilers  and  cleaning  these  every  60  days, 


242  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

taking  three  days  for  a  boiler,  the  cleaning  outfit  would  be  in  use 
over  half  the  time. 

A  satisfactory  substitute  for  this  temporary  cleaning  device 
as  designed  by  the  writer  is  shown  in  Fig.  213  (£4-2).  This 
device,  which  has  the  form  of  a  truck,  is  constructed  with  its  upper 
portion  of  wood  in  the  shape  of  a  shallow  box  with  two  2  by  8  in. 
side  stringers.  The  top  lid,  Ay  when  closed  rests  on  top  of  the 
box.  This  top  is  hinged  at  B,  and  is  supported  on  the  boiler 
fronts  by  the  U-shaped  straps,  C,  into  which  the  hinge  bars  fit. 
This  locking  to  the  front  of  the  boiler  is  quite  necessary  in  order 
to  prevent  the  truck  being  shoved  away  from  the  setting  while  the 
men  are  at  work.  The  cover,  Z),  closes  up  the  top  of  the  box,  thus 
making  a  solid  and  smooth  platform  for  the  men  to  stand  upon. 
The  wheels  are  broad-faced  cast  iron,  and  those  marked  E  are 
casters  which  can  be  rotated  with  the  handle,  F,  loose  jointed  at  G. 
The  cross  pipes,  H,  serve  as  braces  and  steps. 

This  entire  platform  can  be  kept  painted  and  does  not  disfigure 
the  boiler  room.  The  box,  7,  may  be  used  for  storing  the 
cleaning  tools  and  also  for  laying  aside  crabs,  plates,  and  gaskets 
which  are  taken  from  the  boiler  during  cleaning.  The  cover,  D, 
closes  the  box  while  the  turbine  cleaner  is  in  use.  Such  a  truck 
can  be  made  at  a  moderate  cost  by  a  blacksmith,  carpenter,  and 
pipe  fitter.  If  it  is  profitable  to  construct  permanent  metal  plat- 
forms for  cleaning  the  vertical  type  of  water-tube  boilers,  would 
it  not  seem  equally  profitable  to  supply  plants  having  horizontal 
water-tube  boilers  with  devices  for  similar  work  ? 

In  addition  to  the  branches  from  the  auxiliary  main  which  have 
already  been  described,  there  are  numerous  low-pressure  lines. 
These  lines  will  be  described  more  fully  under  Class  H  —  "Low- 
Pressure  Water  Lines."  Ordinarily  it  would  be  safe  to  assume 
that  there  should  be  as  many  water  mains  in  a  plant  as  there  are 
pumps.  If  there  are  two  pumps  there  will  be  but  two  mains 
necessary,  since  it  would  be  necessary  to  cut  a  third  main  into  one 
or  the  other  of  the  first  two  in  order  to  get  water. 


CHAPTER   XV. 
FEED    AND    FIRE    PUMP    SUCTIONS. 

Class  Fl  —  Feed  and  Fire  Pump  Suction  Main,  tinder  ordinary 
conditions,  being  free  from  pressure,  a  suction  line  should  be  simple 
to  construct  and  operate  were  it  not  that  the  water  end  of  a  pump 
has  such  a  large  clearance.  The  chamber  between  the  suction  and 
the  discharge  valves  of  many  designs  of  pumps  is  as  much  as  six 
times  the  volume  of  piston  displacement.  If  absolute  pressure  is 
assumed  as  15  lb.,  the  piston  displacement  in  such  pumps  would 
reduce  the  pressure  in  the  cylinder  to  12.5  lb.,  which  in  case  of 
starting  -a  pump  without  priming  would  make  the  head  about 
2.5  ft.,  an  amount  less  than  that  necessary  to  open  the  suction 
valves.  As  the  amount  of  air  in  the  cylinder  is  lessened  the  ability 
of  the  pump  to  lift  water  is  increased,  and  if  there  were  no  air  in 
the  cylinder  the  amount  of  pump  clearance  would  not  affect  the 
ability  of  the  pump  to  lift  water.  This  absence  of  air,  however,  is 
not  obtainable  in  regular  practice,  and  the  ah*  is  taken  into  the 
cylinder  with  the  water,  through  leaky  joints  and  stuffing  boxes,  or 
gases  are  liberated  from  water  containing  vegetable  matter  in 
solution. 

The  pump  builder's  guarantee  as  to  what  height  of  column  his 
pump  will  lift  is  of  little  or  no  use  in  determining  the  relative  merits 
of  pumps.  Such  pump  comparisons  can  better  be  made  by  using 
the  ratio  of  piston  displacement  to  cylinder  volume  and  the  head 
necessary  to  pass  the  desired  quantity  of  water  through  the  suction 
valve.  All  designs  of  pumps  are  affected  by  air  in  the  cylinder,  and 
when  the  speed  is  lessened  the  quantity  of  air  increases,  which  in 
turn  lessens  the  lift  of  the  pump.  A  pump  which  lifts  water  from 
a  level  26  ft.  below  that  of  the  discharge  valve  must  have  extremely 
tight  connections,  the  water  handled  must  be  free  from  vegetation, 
and  the  pump  be  run  quite  fast  to  prevent  even  a  small  amount  of 
air  from  accumulating  in  the  cylinder.  Such  conditions  are  too 
severe  for  regular  station  work,  and  in  proportion  to  the  shortening 

243 


244  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

of  the  lift  are  pump-suction  troubles  reduced.  It  should  not  be 
inferred  that  pumps  with  short  suction  and  with  excessive  air  leaks 
in  the  suction  connections  are  always  operative,  and  it  is  only  by 
delivering  the  pump  suction  under  a  head  above  that  of  atmos- 
pheric pressure  that  difficulties  caused  by  air  leaks  are  entirely 
eliminated.  In  the  case  of  a  pump  with  a  2-ft.  lift,  or  under  13  Ib. 
absolute  pressure,  delivering  water  at  150  or  165  Ib.  absolute 
pressure,  the  air  would  be  compressed  about  one-thirteenth  of  its 
volume,  which  would  be  equivalent  to  the  volume  displacement  of  a 
piston  with  a  ij-in.  stroke  when  clearance  equals  one  inch  of  stroke. 

About  the  only  practical  way  of  putting  in  service  a  pump  which 
is  unable  to  compress  the  air  to  a  sufficiently  high  pressure  so  that 
ft  will  pass  off  through  the  discharge  valve  when  such  a  large 
amount  has  accumulated,  is  to  discharge  the  air  to  atmosphere 
through  a  pet  cock.  Feed  pumps  should  have  a  valve  larger  in 
area  than  a  pet  cock  located  about  three-quarters  or  one  inch  below 
the  valve  deck.  This  valve  will  provide  a  ready  means  of  dis- 
charging the  air.  Another  method  which  is  sometimes  used,  but 
is  nevertheless  faulty,  is  to  place  a  small  air-discharge  valve  between 
the  pump-discharge  valves  and  the  gate-stop  valve  in  the  pump 
discharge.  To  relieve  a  pump  of  air  it  is  usually  necessary  to  run 
it  at  a  high  speed.  This  is  due  to  the  inability  of  valves  to  hold 
air  properly,  and  when  the  water  does  reach  the  cylinder  it  comes 
in  a  slug.  With  the  valve  in  the  discharge  line  closed  there  is  a 
physical  danger  under  such  circumstances,  as  the  water  pressure 
may  reach  a  destructive  point  in  the  pump  before  the  steam  valve 
can  be  closed  or  the  discharge  opened.  The  advantage  of  closing 
the  discharge  valve  is  to  prevent  water  from  the  pressure  line 
leaking  back  into  the  pump  through  the  pump  valves.  If  the  pump 
is  provided  with  relief  valves  placed  between  the  pump  and  the 
discharge  valve  the  operation  will  be  satisfactory. 

If  the  suction  main  for  a  pump  is  underground  it  should  be  made 
of  cast  iron,  and  if  it  is  subject  to  vibration,  settlement  of  ground, 
or  excessive  expansion  strains,  it  should  be  flanged  and  have  metal 
gaskets.  The  most  satisfactory  arrangement  for  long  underground 
suction  connections  is  to  locate  the  underground  piping  at  a  level 
below  the  water  inlet  or  water  surface  and  build  the  lift  pipe  so 
that  it  is  exposed  free  to  expand  and  opportunity  is  afforded  for 
readily  making  repairs.  Fig.  214  (Fi-i)  will  illustrate  the 
details  of  a  very  satisfactory  arrangement  of  piping  for  such  service. 


FEED   AND   FIRE  PUMP  SUCTIONS. 


245 


The  well  should  be  about  three  feet  in  diameter,  have  a  ladder 
inside  and  a  manhole  top  covering  so  arranged  that  the  suction 
pipe  will  be  supported  from  above.  If  the  water  line,  A,  to  the 
well  is  large,  about  24  or  30  in.  in  diameter,  it  may  be  built  of  clay 
sewer  pipe  with  cemented  joints,  which  will  prevent  any  leakage 
of  sand.  The  construction  of  pump  suction  wells  is  often  expen- 


FIG.  214  (Fi-i). 

sive  even  when  the  work  is  done  with  cheap  material.  The 
location  of  the  suction  line  below  the  water  level  brings  about  many 
difficulties  such  as  the  caving  in  of  the  trench,  the  handling  of 
loose  and  wet  earth,  the  laying  of  pipe  on  a  soft  bottom  while 
water  is  flowing,  and  difficulties  with  the  men  who  are  doing  the 
work,  because  they  must  either  be  ignorant  and  incompetent  men 
who  are  obliged  to  do  such  labor  or,  if  more  capable,  they  are 
working  with  a  grievance. 

For  such  work  sewer  pipe  can  be  used  and  satisfactory  results 
obtained  if  the  work  is  properly  done,  but  under  such  conditions 
as  prevail  in  this  character  of  work  it  is  next  to  impossible  to  lay 
sewer  pipe  properly.  Cast-iron  pipe  is  made  in  longer  lengths, 
which  affords  an  opportunity  for  supporting  the  sections  by  filling 
around  the  centers,  leaving  the  joints  clear  for  calking.  If  pumps 
are  used  to  keep  the  water  away  from  the  work  it  will  be  necessary 
to  have  one  on  either  side  of  the  hole  in  which  the  work  is  carried 
on  so  that  the  water  will  not  interfere  with  the  leading  of  the  joints. 

Another  method  of  constructing  such  a  line  is  illustrated  in 


246 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


Fig.  215  (Fi-2).  With  this  method  the  larger  part  of  the 
cost  is  for  material,  as  the  work  can  all  be  done  with  common 
labor.  Referring  to  the  illustration,  the  form,  A,  is  made  up 
of  plates  connected  by  handles  in  the  shape  of  an  inverted  U. 

In  beginning  the  work  the  trench  is 
first  dug,  then  the  pipe,  B,  is  screwed 
together  and  placed  in  approximately 
its  final  position.  The  metal  form  is 
then  set  about  the  pipe  as  shown  in 
the  drawing,  and  the  space  outside 
of  the  form  filled  with  dirt,  while  the 
inside  of  the  form  is  filled  with  con- 
crete to  encase  the  pipe.  As  soon  as 
the  concrete  and  dirt  have  been 
rammed  the  form  is  withdrawn  and 
the  trench  then  loose  filled  up  to  the 
point,  D,  at  the  bottom  of  the  planking. 
With  this  type  of  construction  old 
pipe  may  be  used,  as  it  is  surrounded 
by  concrete  through  which  no  water 
H° p^  can  leak.  The  work  can  be  carried 

Lz ~J        on  even   when  the   trench   is   wet,  as 

FIG.  215  (Fi-2).  the  pipe  may  serve  to  lead  away  the 

water  during  the  progress  of  the  work 

and  the  concrete  can  be  placed  in  water.  Two  or  three  of  these 
portable  forms  are  required  so  that  they  can  be  moved  ahead  as 
the  work  advances. 

The  most  satisfactory  method  of  executing  the  work  shown 
in  Fig.  214  is  to  build  the  suction  well  before  disturbing  the  out- 
side ground.  With  this  well  in  operating  condition  the  trench 
can  be  dug  from  the  well  toward  the  waterway  and  the  pipe 
laid  as  fast  as  the  dirt  is  removed.  This  will  allow  the  water  in 
the  trench  to  drain  to  the  well,  from  which  it  can  be  removed 
by  the  regular  pump  or  a  temporary  one.  It  is  important  that 
the  joints  in  the  pipe  be  tight  if  they  are  to  be  encased  in  concrete, 
as  water  passing  through  the  fresh  concrete  to  the  inside  of  the 
pipe  will  wash  out  the  cement  and  leave  only  the  loose  material. 
Further  discussion  of  this  subject  as  considered  for  large  suction 
mains  will  be  found  under  the  heading  "  Condenser  Intakes  — 
Class  I." 


FEED   AND   FIRE   PUMP  SUCTIONS. 


247 


Many  suction  lines  are  provided  with  foot  valves  which  aid 
the  pumps  in  holding  their  vacuum.  The  use  of  foot  valves  is 
quite  limited.  If  the  pump  valves  are  in  good  order  the  foot 
valves  will  retard  rather  than  aid  the  pump  in  its  operation. 
When  foot  valves  are  used  the  pump  suction  must  constantly 
support  the  weight  of  the  valve,  which  amounts  to  about  0.5  Ib. 
for  each  square  inch  of  area,  or  an  increased  lift  equivalent  to 
i  ft.  Sometimes  the  operation  of  a  pump  is  improved  by  the 
use  of  a  foot  valve  because  the  suction  valves  fail  to  hold,  but 


FIG.  216  (Fi-3). 


better  results  could  possibly  be  obtained  by  renewing  or  repair- 
ing the  suction  valves.  There  are  some  instances,  however, 
where  foot  valves  are  indispensable  for  pump  starting,  as  is  the 
case  with  pumps  of  the  centrifugal  type  in  which,  when  priming, 
it  is  necessary  to  fill  the  body  of  the  pump  with  water  and  expel 
the  air.  Without  a  foot  valve  in  such  a  pump  the  water  would 
be  lost  through  the  suction.  As  a  centrifugal  pump  is  wholly 
unable  to  remove  the  air  it  must  be  removed  by  filling  the  pump 
with  water  or  by  using  a  steam  ejector  attached  to  the  periphery 
of  the  pump  case.  If  a  steam  ejector  is  used  it  is  not  necessary 
to  use  a  foot  valve,  as  the  ejector  will  support  the  column  of  water 


248 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


in  the  suction  pipe.  Air  could  also  be  removed  with  a  steam 
ejector  from  the  suction  of  a  steam  pump,  but  this  process  would 
not  be  as  simple  as  the  discharging  of  the  air  to  atmosphere  or 
by  priming. 

If  the  steam  pump  has  a  high  lift  and  a  large  clearance  in  the 
cylinder,  air  cannot  be  discharged  without  priming  with  or  with- 
out a  foot  valve.  If  the  ratio  of  the  cylinder  clearance  to  the 
piston  displacement  is  but  as  three  to  one,  the  absolute  pressure 
in  the  cylinder  at  the  end  of  the  stroke  would  be  five  pounds,  or 
the  equivalent  of  a  lo-ft.  lift,  and  for  a  lift  of  over  this  amount 
the  pump  could  be  run  indefinitely  without  taking  water.  It  is 
not  necessary  to  fill  the  suction  pipe  of  a  steam  pump  with  water, 
but  in  nearly  all  cases  the  cylinder  must  be  filled  to  reduce  the 
clearance. 

In  Fig.  216  (Fi~3)  is  shown  a  very  simple  starting  arrangement 
for  a  pump  that  connects  with  a  line  which  always  is  filled  with 

water.  The  pipe  lines,  A,  can  be 
turned  on  and  with  the  valve,  B,  open 
to  furnish  an  outlet  for  air  (and  water 
also  in  starting)  and  the  stop  valve,  C, 
closed,  the  pump  being  protected 
against  excess  pressure  by  the  relief 
valve,  D,  can  then  be  started  and  the 
air  removed  without  difficulty.  The 
lines,  A,  are  the  priming  pipes  and 
may  be  connected  to  any  water  supply, 
as  pressure  is  not  required. 

That  a  pump  requires  priming  to 
lift  its  water  does  not  in  the  least 
affect  its  efficiency  unless  possibly  it 
be  increased  by  the  reduced  friction 
of  the  larger  waterways.  If  priming 
water  is  not  readily  obtainable,  or  if 
a  pump  of  the  centrifugal  type  is  used, 
a  very  satisfactory  foot  valve  may  be 
FIG.  217  (Fi-4).  built  as  shown  in  Fig.  217  (Fi~4). 

With  the  valve  so  constructed,  if  the 

pump  is  to  be  shut  down  the  valve  can  be  lowered  so  that  it 
will  bear  on  its  seat  and  operate  the  same  as  the  more  common 
types  of  foot  valves.  While  the  pump  is  in  operation  the  valve 


FEED   AND   FIRE  PUMP   SUCTIONS.  249 

can  be  raised  clear  of  its  seat.  When  the  pump  is  out  of  service 
the  valve  can  be  closed  tightly.  A  valve  so  constructed  has  so  little 
service  to  perform  that  it  should  require  practically  no  care  or 
attention  to  keep  it  in  perfect  operating  condition. 

Class  F2  —  Feed  and  Fire  Pump  Suction  to  Pumps.  It  is 
often  found  necessary  to  connect  the  different  suctions  to  one 
suction  main.  Such  an  arrangement  should  be  avoided  if  pos- 
sible and  the  more  satisfactory  one  as  shown  in  Fig.  214  be 
used.  This  arrangement,  with  the  separate  suctions  from  each 
pump  to  the  well,  permits  of  free  expansion  and  contraction  of 
the  line  and  facilitates  repairs  on  any  branch  without  interfering 
with  the  operation  of  neighboring  pumps.  The  arrangement 
with  separate  suction  pipes  does  away  with  shut-off  valves,  and 
air  chambers  can  be  omitted  at  the  ends  of  the  suction  branches. 
In  fact,  the  operation  of  the  pumps  is  made  comparatively  simple, 
while  on  the  other  hand  connecting  the  different  pump  suctions 
into  one  main,  more  particularly  if  this  main  is  of  considerable 
length,  brings  about  many  difficulties. 

If  several  suction  lines  are  to  be  connected  to  one  main  the 
piping  must  be  sufficiently  large  to  supply  all  the  pumps,  thus  in- 
creasing the  size  and  number  of  the  joints.  A  large  main  located 
above  the  water  level  and  supplying  several  pumps  should  have 
a  foot  valve  at  its  end  to  prevent  emptying,  otherwise,  if  the 
suction  were  lost,  considerable  time  would  be  required  in  which 
to  remove  the  air  accumulated  in  the  large  pipes.  In  any  event 
long  suction  mains  are  troublesome,  and  to  avoid  the  shock  due 
to  the  starting  and  stopping  of  the  large  column  of  water  con- 
tained therein,  which  movements  are  due  ,to  the  action  of  the 
pumps,  it  is  necessary  to  use  an  air  chamber  which  will  absorb 
the  impact.  The  use  of  a  foot  valve  in  connection  with  such  a 
combination  of  suction  pipes  results  in  the  saving  of  the  energy  of 
the  moving  column. 

To  be  effective  in  relieving  the  pumps  from  shock  an  air 
chamber  must  be  located  so  that  the  flow  from  the  suction  lines 
is  direct  to  the  chamber,  and  the  opening  in  the  chamber  should 
be  of  the  full  size  of  the  pipe  as  is  shown  in  Fig.  218  (F2-i). 
If  the  suction  chamber  contains  no  obstructions  the  air  chamber 
may  be  placed  on  the  side  of  the  pump  opposite  the  suction. 
In  no  case  should  the  air  chamber  be  attached  to  the  side  out- 
let of  a  tee.  The  difficulties  occasioned  by  water  flowing  to  the 


2$0  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

pumps  are  not  due  to  pressure  but  to  inertia.  When  water  is 
brought  to  rest  it  should  not  be  necessary  to  create  a  pressure  in 
the  line  in  order  that  the  column  of  water  may  be  diverted  into 
an  air  chamber,  nor  should  it  be  necessary  to  set  other  water  in 
motion  which  would  in  turn  flow  into  the  air  chamber;  it  is  this 
sudden  retarding  of  moving  water  that  causes  water  hammer. 


FIG.  218  (Fz-i). 


FIG.  219  (F2-2). 


In  case  the  suction  must  be  long  and  connected  with  two  or 
more  pumps  it  is  necessary  to  cushion  the  movement  of  the  long 
heavy  body  of  water  with  as  little  obstruction  between  it  and 
the  air  cushion  as  possible.  Fig.  219  (¥2-2)  illustrates,  in 
full  lines,  a  complete  system  for  cushioning  the  entire  moving 
body  of  water  except  the  smaller  amount  in  the  air  chambers, 
which  amount  is  negligible  in  effect.  If  the  pumps  are  close 
together,  with  a  short  main  connecting  them,  one  air  chamber,  as 
indicated  at  A,  may  be  used  to  absorb  the  impact  of  the  long 
line,  thus  allowing  the  inertia  of  the  water  in  the  connecting 
main  to  be  taken  up  or  dissipated  in  pumps  without  air  cham- 
bers. In  no  case  should  the  air  chamber  be  placed  at  B,  because 
it  then  would  not  cushion  the  movement  of  the  long  line,  due  to 
the  fact  that  a  large  portion  of  the  water  in  the  horizontal  main 
would  be  at  rest  at  the  time  of  impact.  Before  this  body  of  water 
could  move,  the  shock  would  be  taken  up  throughout  the  pip- 
ing. Such  shocks  are  usually  very  severe  and  are  often  sufficient 
in  amount  to  break  the  fittings  even  though  practically  no  pres- 
sure is  observed  on  the  line.  An  air  chamber  on  a  long  suction 
causes  a  pump  to  work  more  smoothly  than  otherwise,  reduces 
steam  consumption,  and  though  it  can  be  dispensed  with  in  cer- 
tain cases  it  is  in  no  case  an  objectionable  feature. 

Class  F3  —  Feed  and  Fire  Pump  Suction ;  Branch  for  Heater. 
The  suction  branch  used  in  connection  with  open  heaters  serves 
to  handle  water  which  in  many  cases  is  of  a  sufficiently  high 


FEED    AND   FIRE   PUMP  SUCTIONS.  25! 

temperature  to  form  a  vapor  if  the  pressure  falls  below  the  atmos- 
pheric point.  To  avoid  reducing  the  pressure  to  a  troublesome 
point  it  is  necessary  to  place  the  heater  at  an  elevation  sufficiently 
high  above  the  pump  so  that  the  head  of  water,  measured  from 
the  water  level  in  the  heater  to  the  discharge  valves,  will  exceed 
that  required  to  overcome  the  friction  of  the  pipe,  water  ports, 
and  the  resistance  of  the  pump  suction  valves.  By  increasing 
the  suction  connections  to  one  size  larger  than  the  pump  open- 
ing and  by  reducing  the  tension  of  the  springs  on  the  suction 
valves  this  difference  of  elevation  has  been  made  as  low  as  2  ft., 
but  for  safe,  reliable  operation  a  head  of  from  4  to  5  ft.  should  be 
provided. 

The  heater  should  be  placed  as  close  to  the  pumps  as  pos- 
sible and  the  friction  of  the  connections  be  reduced  by  using 
bends  and  long-radius  fittings.  This  class  of  service  requires 
a  special  hot- water  pump  whose  parts  are  free  from  rubber  and 
which  is  packed  with  some  material  not  affected  by  hot  water. 
Under  ordinary  conditions  metal  valves  with  brass  plungers  and 
rods  that  pass  through  the  packing  are  suitable.  When  work- 
ing in  extremely  hot  water  the  packing  will  not  retain  a  lubri- 
cant, and  for  this  reason  a  dense  surface-metal  is  required  to 
avoid  cutting  or  wearing  out  of  the  packing.  Cast-iron  plungers 
are  too  porous  and  steel  stems  are  quickly  roughened  by  rust. 
Brass  plungers  passing  through  outside  packing  and  bronze  valve 
rods  are  found  most  satisfactory  for  this  service. 

Class  F4  —  Feed  and  Fire  Pump  Suction ;  Branch  from  Hot-Well. 
The  hot-well  should  have  a  separate  compartment  for  the  pump 
suction.  The  supply  to  this  compartment  should  be  so  arranged 
that  the  pump  will  not  take  any  of  the  air  discharged  by  the  con- 
denser and  the  suction  water  be  free  from  agitation  caused  by  the 
condenser  discharge,  which  in  turn  would  cause  such  cylinder  oil 
as  might  enter  the  hot-well  to  be  mixed  with  the  water.  The  hot- 
well  should  also  be  arranged  so  that  the  surface  of  the  pump-water 
compartment  is  constantly  being  drawn  off.  This  will  remove 
any  such  oil  as  may  rise  to  the  surface.  The  pump  suction  should 
be  so  placed  that  it  cannot  remove  the  water  from  the  hot-well  and 
cause  the  water  seal  to  be  broken  when  starting  the  condenser. 
These  various  requirements  are  quite  simply  met  with  in  the 
arrangement  shown  in  Fig.  220  (F4-i).  In  this  plan  the  pump 
suction  is  located  at  a  low  position  which,  as  far  as  possible,  will 


252 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


allow  oil  to  rise  to  the  surface  and  escape.  The  partition  at  A 
should  be  a  trifle  lower  than  the  other  partitions.  This  will  insure 
the  water  passing  through  the  pump  box  rather  than  to  the  over- 
flow. The  pump  suction  should  reach  as  low  a  level  as  possible 
so  that  the  suction  of  air  will  be  reduced  to  a  minimum. 


n 


FIG.  220  (F4-i). 

If  the  suction  line  is  of  considerable  length  (over  50  ft.)  it  should 
discharge  into  a  small  suction  well  and  the  pump  suction  be  taken 
from  this  well.  If  the  condensers  are  of  the  low-down  jet  type 


FlG.    221    (F4-2). 

with  vacuum  pumps  the  pump  box  would  be  quite  similar  to  the 
hot- well,  this  box  being  located  at  some  point  along  the  condenser 
discharge  and  convenient  for  the  pump  suction.  Fig.  221 
(F4~2)  shows  a  pump  box  in  the  discharge  line  from  the  condenser, 
the  box  taking  the  place  of  an  elbow.  With  such  a  box  the  dis- 


PEED   AND  FIRE  PUMP  SUCTIONS, 


253 


charge  may  be  run  straight  through  as  shown  by  the  dotted  lines 
at  A.  Such  a  box  may  be  constructed  in  various  forms,  but  the 
following  requirements  should  be  observed:  "Water  enters  pump 
box  at  top,"  "water  passes  over  top  on  way  to  discharge,"  and 
"water  shall  flow  to  pump  box  rather  than  to  overflow." 

The  function  of  the  pump  box  is  to  avoid  oil  and  air  in  the  con- 
denser discharge.  This  object  is  very  essential,  and  if  the  water 
carries  other  impurities  or  an  excessive  quantity  of  oil  it  will  be 
found  advisable  to  pass  the  pump  water  through  excelsior  and 
renew  this  excelsior  filter  as  often  as  it  becomes  clogged  with  oil. 


FIG.  222  (F4-3). 

Fig.  222  (F4~3)  shows  such  a  filter  so  arranged  that  it  can  be 
inverted  while  the  condenser  is  in  operation,  thus  raising  the  entire 
filtering  device  out  of  the  water,  revolving  it  on  the  line,  AB. 
When  the  filtering  device  is  to  be  rolled  the  handle,  C,  is  used  to 
release  the  pipe  union  connecting  the  filter  chamber  and  the  pump 
box.  The  space,  D,  is  filled  with  excelsior,  and  screens  are  placed 
at  E,  so  that  they  will  retain  the  filling.  The  joint  between  the 
filter  case  and  the  pump  suction,  which  is  of  the  tongue  and  groove 
type,  may  be  made  of  leather. 

There  are  many  other  materials  that  may  be  used  for  this 
work,  but  excelsior  is  cheap,  easily  handled,  and  has  a  great 
affinity  for  oil  and  grease,  which,  coupled  with  the  fact  that  it  is 
readily  disposed  of  in  the  boiler  furnace,  make  it  a  very  suitable 
material  for  the  purpose.  The  filter  box  can  be  cleaned  by  lifting 
the  foul  excelsior  with  a  pitchfork  and  carting  it  away  in  a  wheel- 
barrow. A  plant  provided  with  such  a  device  and  using  water 
containing  a  large  amount  of  impurities  in  addition  to  cylinder  oil, 
uses  i  cu.  ft.  of  excelsior  for  each  loo-hp.  capacity  of  boilers. 
The  filter  in  this  plant  must  be  cleaned  once  a  week,  because 
the  excelsior  then  becomes  very  foul.  The  waste  excelsior 


254 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


is  very  black  and  has  oil  and  grease  thoroughly  absorbed  into  the 
wood ;  this  is  quite  a  different  action  from  that  of  material  which 
would  merely  filter,  as  excelsior  serves  more  as  an  absorbing 
medium. 

The  gage,  F,  shown  in  Fig.  222,  is  used  to  indicate  the  condition 
of  the  filter  bed.  When  this  bed  is  clear  and  unobstructed  the 
gage  may  show  5  in.  of  vacuum  (depending  upon  the  lift),  and  as 
it  becomes  foul  it  may  show  6  or  7  in.,  due  to  the  passage  of  the 
water  through  the  bed  becoming  obstructed. 

If  the  principal  impurity  in  water  is  sand  or  small  particles  a 
better  filter  can  be  constructed  with  a  series  of  screens,  as  in  this 
case  the  mesh  would  be  uniform  and  as  fine  as  desired,  this  quality 
being  unattainable  with  excelsior  or  other  fibrous  materials. 


FIG.  223  (F4-4). 

A  method  of  constructing  such  a  filter  box  with  screens  .is  shown 
in  Fig.  223  (F4-4).  Water  from  the  condenser  enters  at  A, 
and  discharges  at  B,  the  oil  passing  over  the  overflow.  The  four 
tension  rods  are  provided  with  hand  wheels,  C,  and  are  supported 
at  the  opposite  end  of  the  box  in  the  bearings,  Z),  which  will  permit 
of  rotation.  The  frame,  E,  is  metal,  with  threaded  connections  to 
the  tension  rods ;  the  frame,  F,  is  also  made  of  metal,  but  is  attached 
to  the  shell  of  the  tank.  The  frames,  G,  are  of  cypress  or  other 
wood  that  will  wear  well  in  water  and  support  the  screens.  If  it  is 
desired  to  remove  the  screens  from  the  frame,  G,  the  frame,  E,  is 
released  with  the  hand  wheels,  C.  This  allows  the  screens  to  be 
lifted  off  the  upper  rods. 

In  operation  the  water  enters  through  the  metal  frame,  E,  and 
passes  through  all  the  screens  to  the  pump  suction  as  shown  in  the 
illustration.  If  there  is  a  slight  leak  around  the  frame  no  difficulty 
will  be  occasioned  unless  the  leak  opening  is  so  large  that  the 
filtered  impurities  can  pass  through  it.  Ordinarily  the  tension  on 


FEED   AND   FIRE   PUMP   SUCTIONS.  2$$ 

the  screws  will  prevent  this  leakage.  The  filtering  material  may 
be  cloth  instead  of  metal,  and  when  the  screens  are  being  removed 
they  should  first  be  washed  in  the  water  in  the  box,  thus  allowing 
the  impurities  to  remain  in  the  tank  and  be  taken  out  at  one  time, 
when  all  the  screens  are  removed.  The  screens  may  be  graded  in 
mesh  starting  with  coarse  metal  and  finishing  with  fine  cloth. 
Such  a  device  may  strictly  be  called  a  filter  and  operates  very 
satisfactorily  in  removing  fine  silt  and  mud.  If  a  connection  is 
provided  for  draining  the  bottom  of  the  box  the  screens  can  be 
washed  with  a  hose  without  removing  them,  but  they  should  first 
be  loosened  by  releasing  the  clamp  screws.  A  gage  on  the  suction 
pipe  will  serve  to  show  the  condition  of  the  screens. 

Class  F5  —  Feed  and  Fire  Pump  Suction ;  Branch  from  Intake. 
A  suction  branch  from  the  intake  should  be  provided  in  addition 
to  the  suction  line  from  the  hot-well,  as  at  any  time  it  may  be  found 
necessary  to  shut  down  the  condensing  apparatus.  If  two  or  more 
pumps  are  used  the  suction  lines  should  be  arranged  so  that  the 
feed  pumps  may  be  using  hot-well  water  while  the  general  service 
water  is  taken  from  the  intake.  This  arrangement  would  be 
quite  essential  in  a  plant  having  journals  or  any  other  apparatus 
water-cooled. 

Class  F6  —  Feed  and  Fire  Pump  Suction  Branch;  from  City 
Water  Mains.  It  is  invariably  good  practice  to  provide  a  suction 
connection  with  the  city  water  supply  which  can  be  used  in  case  of 
need  even  though  a  plant  has  its  own  source  of  water  supply  as 
from  a  stream,  canal,  pond,  or  deep  well.  The  city  water  should 
discharge  into  an  open  well  or  at  a  point  that  will  be  suitable  for 
"the  pump  suctions.  The  connecting  of  city  lines  direct  to  pump 
suctions  will  cause  some  difficulties,  but  if  such  connections  must 
be  used  an  air  chamber  should  be  provided  which  will  prevent 
water  hammer  in  the  city  water  lines,  meters,  etc.  The  fact  that 
the  suction  water  comes  to  a  pump  under  pressure  is  more  of  an 
advantage  than  otherwise,  as  the  work  of  the  pump  is  lightened 
and  difficulties  from  air  in  the  lines  are  eliminated.  Any  pump 
will  operate  more  satisfactorily  with  the  pressure  head  on  its  suction. 

If  the  city  water  is  connected  direct  to  the  pump  suction  and  the 
other  suction  be  from  a  well,  stream,  or  the  like,  there  should  be  a 
foot  valve  at  the  regular  low-pressure  suction  so  as  to  avoid  any 
possibility  of  wasting  city  water  back  through  the  regular  suction. 
Ordinarily  it  is  advisable  to  place  a  vacuum  gage  on  the  pump 


256  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

suction,  and  in  case  city  water  is  also  used  this  gage  should  be 
compound,  showing  both  pressure  and  vacuum.  With  such  a 
gage  as  normally  operated  the  attendant  can  quickly  note  any 
change  brought  about  by  altered  conditions,  thus  enabling  him  to 
remedy  a  difficulty  before  it  becomes  serious.  Such  troubles 
may  be  from  the  foot  valve,  pump-suction  valve,  accumulation 
in  suction  line,  city  water  under  pressure  leaking  past  its  stop 
valve,  or  from  numerous  similar  causes.  The  saying  "  A  stitch  in 
time  saves  nine"  is  very  applicable  in  station  operation,  and  such 
devices  as  aid  in  anticipating  trouble  in  power  stations  are  well 
worth  the  expense  of  installation. 

Class  F7  —  Feed  and  Fire  Pump  Suction ;  Branch  from  Econ- 
omizer. The  suction  branch  from  the  economizer  is  only  used 
where  boilers  are  operated  under  an  extremely  high  pressure, 
say  200  lb.,  and  where  it  is  desired  to  operate  the  economizers  under 
a  low  pressure,  say  40  lb.  Such  a  system  was  shown  in  Fig.  6, 
which  may  be  found  in  an  early  chapter.  The  chief  requirement 
of  the  suction  line  from  the  economizer  is  that  it  may  be  maintained 
under  the  set  pressure  of  40  lb.  if  it  be  so  set,  thus  avoiding  the 
possibility  of  the  hot  water  from  the  economizer  forming  a  vapor. 
At  40  lb.  pressure  water  can  be  heated  as  high  as  286°  F.  before 
difficulty  will  be  encountered  from  steam  vapor  in  the  feed-pump 
suction.  If,  however,  the  economizers  raise  the  temperature  of 
the  water  above  this  point,  which  would  be  a  rare  case,  the  pressure 
may  be  increased  sufficiently  to  avoid  vapors.  The  pump  cylinders 
would  show  slightly  less  pressure  than  the  line  to  the  pump, 
possibly  two  pounds,  which  would  necessitate  raising  the  pressure 
a  like  amount  to  balance  this  loss. 

The  pump  which  supplies  an  economizer  must  be  sensitive  to 
pressure  and  preferably  should  have  a  governor  which  controls 
for  a  fixed  pressure.  If  the  lowest  pressure  be  above  a  possible 
steaming  point  no  serious  result  would  arise  if  the  pressure  in  an 
economizer  varied  within  a  considerable  range.  A  quite  simple 
method  of  controlling  water  fed  to  an  economizer,  as  has  been 
described,  is  to  use  a  motor-driven  centrifugal  pump,  possibly  of 
the  two-stage  type,  and  allow  this  pump  to  run  continuously, 
the  head  under  which  it  would  operate  being  equivalent  to  84  ft., 
which  is  ordinary  service  for  a  two-stage  pump. 

Class  F8  — Feed  and  Fire  Pump  Suction;  Branch  from  Storage 
Tank  or  Basin.  The  line  from  a  storage  tank  or  basin  is  a  rather 


FEED   AND   FIRE  PUMP  SUCTIONS. 


257 


unusual  suction  connection,  being  virtually  a  suction  from  some 
tank  into  which  a  pump  discharges.  This  branch  is  quite  neces- 
sary if  there  is  but  one  source  for  obtaining  water.  The  storage 
tank  ordinarily  would  be  used  as  a  general  low-service  reservoir 
supplying  water  by  gravity  pressure.  The  pump  would  raise 
water  to  this  tank,  and  if  for  any  reason  it  be  found  necessary  to 
shut  off  the  regular  pump-suction  supply  the  tank  water  will  be 
available  for  use  as  boiler  feed  or  for  any  other  water  supply  which 
must  be  maintained  constantly.  If  there  is  another  means  of  secur- 


FIG.  224  (F8-i). 


ing  water  it  is  quite  unnecessary  to  make  this  connection  unless 
there  are  two  or  more  supplies  which  are  insufficient  for  fire  service 
and  water  in  storage  is  desired  for  this  purpose.  This  would  be 
the  case  if  the  plant  had  two  wells  of  limited  capacity.  The  only 
objection  to  such  a  system  is  the  somewhat  complicated  arrange- 
ment of  valves  necessary  to  transfer  the  pump  suction  and  discharge 
and  the  possible  confusion  which  may  be  occasioned  in  handling 
such  valves,  more  particularly  in  case  of  excitement  at  the  time  of 
an  alarm  of  fire. 

Fig.  224  (F8-i)  illustrates  the  connections  to  a  large  low- 
pressure  water  storage  with  a  tell-tale  for  showing  the  relative 
water  level.  The  well,  A,  as  shown,  usually  is  so  limited  in 


258  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

capacity  that  it  is  quite  unfit  for  fire  service,  but  by  constant 
pumping  ample  water  may  be  obtained  at  such  times  for  the 
boilers  and  also  to  keep  the  water  basin,  B,  well  filled.  For  the 
storage  of  a  large  amount  of  water  such  a  basin  is  practical  only 
when  at  a  low  elevation,  as  otherwise  the  expense  for  building  a 
high  structure  would  be  excessive.  The  line,  C,  is  the  fire  main 
and  is  regularly  used  as  a  low-pressure  service  main.  Whenever 
the  water  in  the  basin  is  low  and  the  pump  is  not  in  use  for  boiler 
feeding  or  other  high-pressure  work,  the  valve,  D,  is  open  and 
the  valve,  E,  closed;  thus  water  is  delivered  to  the  basin  through 
the  pump  discharge,  F.  The  valve,  G,  is  always  closed  and  the 
valves,  H,  and  J  are  always  open  except  in  case  of  fire.  With 
such  a  system  it  would  be  necessary  to  number  the  valves  which 
should  be  operated  in  numerical  order  in  case  of  fire,  thus  avoiding 
any  possibility  of  the  two  suctions,  H  and  G,  being  open  at  the 
same  time. 

In  regard  to  the  proper  handling  of  valves,  pumps,  etc.,  at  the 
time  of  fire,  it  is  becoming  quite  general  practice  to  have  regular 
fire  drills  which  will  accustom  the  men  to  their  duties,  so  that  in 
emergencies  such  errors  as  have  been  stated  will  not  be  made. 
In  many  installations  the  well,  A,  Fig.  224,  is  a  deep-driven  one 
with  a  regular  deep-well  pump  to  raise  the  water.  Under  such 
conditions  there  should  be  no  confusion  at  times  of  emergency,  as 
the  deep-well  pump  would  discharge  to  the  storage  basin,  B,  and 
the  feed  and  fire  pumps  would  take  their  suction  from  this  storage 
supply. 


CHAPTER    XVI. 
HEATER    WATER    SUPPLY    PIPING. 

Class  Gl  —  Heater  Water  Supply;  from  Condenser.  There  are 
four  possible  types  of  branches  for  supplying  water  from  con- 
densers to  heaters.  These  may  connect  surface  or  jet  conden- 
sers with  open  or  closed  heaters.  In  Figs.  220  and  221  suction 
boxes  are  shown  as  a  part  of  the  jet-condenser  discharges.  If 
a  closed  heater  is  used  its  water  supply  may  be  taken  directly 
from  the  pump  box  and  the  boiler-feed  pump  be  used  for  this 
purpose  if  the  lift  is  not  too  great.  The  steam  temperature  at 
25  in.  of  vacuum  is  approximately  135°  F.  If  the  water  from 
the  condenser  has  this  temperature  it  will  vaporize  when  the 
pressure  is  lowered  to  a  point  less  than  that  at  which  it  was  con- 
densed. A  25-ft.  lift  would  bring  about  conditions  suitable  for 
vaporization,  but  water  at  a  temperature  of  135  degrees  and  a 
lift  of  25  ft.  are  not  met  with  in  practice.  The  capacity  of  a 
condenser  (condensing  volume)  is  usually  restricted,  for  com- 
mercial reasons,  so  that  the  common  type  of  condenser  requires 
its  discharge  water  to  be  of  considerably  lower  temperature  than 
the  steam  under  vacuum. 

Very  few  jet  condensers  will  maintain  a  vacuum  of  25  in.  with 
the  tail-water  above  100°  F.,  and  in  most  cases  90  degrees  is  con- 
sidered high.  In  regard  to  the  vaporizing  of  tail-water  when 
the  pressure  has  been  reduced  by  the  suction  of  the  pump,  it  can 
be  stated  that  it  is  possible  to  lift  such  water  as  many  feet  as  there 
would  be  inches  of  vacuum  and  water  at  its  highest  possible 
temperature.  This,  however,  has  not  been  found  possible  in 
practice  because  of  other  elements  than  vaporizing  which  must 
be  considered.  The  most  important  obstacle  is  the  gas  liber- 
ated at  heats  as  low  as  90  degrees,  this  gas  being  thrown  off  from 
the  organic  matter  found  in  the  water. 

The  presence  of  such  a  gas  is  quite  fully  demonstrated  by  the 
action  of  a  dry-vacuum  air  pump  in  which  it  is  noted  that  a  much 
higher  rate  of  speed  is  necessary  in  the  summer  season  to  remove 

259 


260  STEAM  POWER   PLANT  PIPING  SYSTEMS. 

the  larger  quantity  of  air  due  to  the  fact  that  the  water  contains 
vegetation  that  it  does  not  contain  in  the  winter.  The  tem- 
perature of  the  tail-water  is  practically  the  same  for  both  seasons, 
but  its  quantity  is  reduced  during  the  winter.  It  has  been 
further  noted  that  during  winter  months  the  vacuum  will  not 
drop  more  than  an  inch  below  25  in.  when  the  air  pump  is  out 
of  service,  but  during  the  summer  months  the  vacuum  will  drop 
4  or  5  in.  under  similar  conditions. 

By  arranging  the  hot-well  as  shown  in  Fig.  220  (F4~i) 
the  liberated  gases  will  not  be  taken  into  the  suction  line,  and  if 
the  suction  lift  is  not  greater  than  12  ft.  little  or  no  trouble 
should  be  experienced  by  pumps  losing  their  water  due  to  gases 
accumulating  in  the  pump  cylinders.  To  further  insure  the  suc- 
cessful operation  of  the  feed  pumps  working  under  these  con- 
ditions the  size  of  the  pump  should  carefully  be  considered  in 
connection  with  the  work  which  it  is  to  do.  The  smaller  the 
pump  the  greater  the  number  of  strokes  and  lesser  liability  of 
becoming  "air-bound,"  or  in  other  words,  losing  its  suction. 

If  an  open  heater  is  used  with  a  jet  condenser  it  will  be  found 
necessary  to  install  a  hot-well  pump  for  delivering  water  to  the 
heater.  This  pump  will  be  necessary  on  account  of  the  usual 
conditions  which  determine  the  location  of  the  hot-well  at  a  low 
elevation  and  the  heater  at  a  much  higher  one.  With  an  ele- 
vated jet  condenser  a  very  simple  method  of  handling  water  to 

the  heater  is  as  shown  in  Fig. 
225  (Gi-i).  In  this  arrange- 
ment the  same  motor  or  belt 
drive  that  operates  the  injection- 
water  pump  is  also  used  to 
operate  the  heater-supply  pump. 
A  float-operated  valve  such  as  is 
regularly  furnished  with  open 
heaters  may  be  arranged  to 
FIG.  225  (Gi-i).  control  the  water  fed  to  the 

heater,   the    centrifugal    pump 

maintaining  the  same  speed  for  varying  requirements.     The  unit 
shown  in  Fig.  225  is  free  from  pump  valves  and  reciprocating 
parts.     It   thus  requires  very  little   attention  and  the  cost  for 
maintenance  is  quite  low. 
If  it  is  necessary  to  raise  the  hot-well  water  to  the  feed  pump 


HEATER   WATER   SUPPLY   PIPING. 


261 


where  a  closed  heater  is  used,  this  same  arrangement  as  shown 
in  Fig.  225  may  be  used  and  the  discharge  from  the  small  cen- 
trifugal pump  piped  direct  into  the  feed-pump  suction.  A  pump 
of  the  centrifugal  type  is  the  only  one  that  can  be  operated  suc- 
cessfully when  discharging  into  the  suction  line  of  another  pump. 
It  is  also  the  only  type  which  can  vary  in  capacity  without  having 
its  speed  altered. 

There  is  the  same  opportunity  for  choice  in  the  branches  from 
a  surface  condenser  to  the  heater  as  was  stated  for  jet-condenser 
conditions.  The  surface  condenser  requires  a  pump  to  with- 


FIG.  226  (Gi-2). 

draw  the  condensation.  This  condensation  is  fed  to  the  heater 
instead  of  the  circulating  water  as  with  the  jet  condenser.  If 
the  pump  is  made  amply  heavy  for  duty  in  boiler  feeding  it  can 
also  serve  both  purposes  as  shown  in  Fig.  226  (Gi-2).  This 
arrangement,  of  course,  applies  only  to  the  use  of  closed  heaters 
as  shown  in  the  illustration.  The  feed  pump  in  this  case  would 
be  controlled  by  the  amount  of  condensation  in  the  pocket,  0,  the 
float  in  this  pocket  operating  the  valve  of  the  pump. 

With  the  arrangement  as  shown  it  would  be  necessary  to  have 
one  or  more  feed  valves  open  at  all  times  to  avoid  the  loss  of  con- 
densed water.  In  fact,  this  is  necessary  in  any  piping  system 
using  a  surface  condenser.  Such  steam  as  condenses  in  other 
parts  of  the  system  outside  of  the  condenser  itself  must  be 
replaced  by  water  added  to  the  condensation,  This  is.  an  almost 


262  STEAM   POWER   PLANT   PIPING  SYSTEMS. 

invariable  quantity,  and  the  loss  can  be  provided  for  by  leaving 
the  by-pass,  b,  open  wide  enough  to  allow  a  sufficient  amount  of 
circulating  water  to  be  admitted  into  the  vacuum  chamber  of 
the  heater  and  from  there  pass  with  the  condensation  to  the 
pump. 

The  relief  valve  shown  in  the  illustration  should  be  so  located 
that  if  it  discharges  a  boiler-room  operator  can  readily  notice  it 
and  open  a  feed  valve,  thus  avoiding  any  waste  of  condensation. 
If  the  feed  valves  are  properly  handled  this  relief  valve  should 
never  discharge.  Hand-operated  feed  valves  will  be  found 
much  more  satisfactory  with  this  piping  system  than  any  auto- 
matic feeding  devices.  With  the  hand-operated  valve  it  is  pos- 
sible to  save  the  water  of  condensation  at  all  times,  and  but  little 
regulation  should  be  required,  as  the  float  will  control  the  speed 
of  the  pump  according  to  the  amount  of  condensation  in  the 
pocket  at  the  bottom  of  the  condenser. 

The  pump  may  be  located  out  of  reach  of  the  fireman.  The 
by-pass,  b,  should  be  quite  small  and  of  a  size  which  will  supply 
steam  to  the  system  to  make  up  for  that  which  is  fed  to  the  auxil- 
iaries. This  make-up  will  not  ordinarily  exceed  10  per  cent  of  the 
total  amount  of  water  fed  the  boilers.  The  by-pass  would,  there- 
fore, be  about  two  inches  in  diameter  for  a  plant  having  5,000  hp. 
boiler  capacity.  It  may  be  found  convenient  to  run  the  by-pass 
piping  to  a  point  in  the  boiler  room  where  a  hand  wheel  can  be 
placed  so  that  it  can  be  operated  by  the  fireman. 

The  pump  used  for  this  service  would  not  be  subjected  to  the 
pounding  strains  common  to  the  so-called  air  pump,  which  removes 
both  air  and  water  from  the  condenser.  A  separate  dry-vacuum 
air  pump  would  be  required  with  the  system  as  shown.  Such  a 
pump  is  necessary  for  perfect  operation.  The  feed  pump  would 
be  called  upon  to  handle  nothing  but  solid  water,  but  in  order  to 
assure  this  it  is  necessary  to  place  the  pump  a  sufficient  distance 
below  the  water  line  in  the  bowl,  a,  to  make  certain  that  the  water 
will  pass  to  the  cylinder  without  lowering  the  pressure  therein. 

If  an  open  heater  is  used  the  condensation  pump  may  be  of  a 
lighter  design  and  arranged  to  discharge  the  condensation  into 
the  heater  without  any  restricting  device  operated  by  the  water 
level  in  the  heater.  Such  a  pump  may  handle  air  and  water 
together  and  discharge  both  into  the  open  heater.  This  arrange- 
ment, however,  requires  a  separate  pump  for  boiler  feeding.  It  is 


HEATER   WATER  SUPPLY   PIPING. 


263 


practical  to  run  the  auxiliaries  condensing,  not  using  a  heater,  and 
thus  have  little  or  no  water  passing  through  the  by-pass,  b.  Such 
practice,  however,  is  far  from  economical.  A  steam  pump  will  not 
use  more  than  50  B.t.u.  per  Ib.  of  steam  delivered  to  it  if  the  re- 
mainder, in  exhaust,  is  delivered  to  the  feed  water,  but  an  engine 
will  require  the  expenditure  of  1,100  B.t.u.  per  Ib.  of  steam  delivered 
to  it.  In  other  words,  the  pump  can  use  22  times  as  much  steam 
per  horsepower  as  the  engine  and  yet  be  as  economical  if  all  the 
heat  of  the  exhaust  is  taken  up  by  the  feed  water.  It  will  thus  be 
noted  that  no  engine  is  operative  with  a  sufficiently  small  number 
of  pounds  of  steam  per  horsepower,  nor  is  any  steam  pump  suffi- 
ciently wasteful  of  steam  to  warrant  running  a  feed  pump  con- 
densing, even  though  it  is  possible  to  reduce  the  steam  consumption 
of  a  feed  pump  to  that  of  the  most  economical  steam  unit  known. 


FIG.  227 


Another  method  of  delivering  water  to  a  heater  by  means  of  a 
suction  pump  from  a  low-down  type  of  jet  condenser  is  by  elevating 
the  discharge  to  such  a  height  that  the  water  will  flow  into  the  open 
heater  by  gravity  as  shown  in  Fig.  227  (Gi-3).  When  con- 
sidering such  a  connection  it  should  be  remembered  that  for  every 
foot  the  discharge  is  raised,  as  shown  by  the  dimension  line,  a, 
this  lift  is  equivalent  to  raising  the  feed  water  30  times  this  amount, 
as  the  quantity  thus  lifted  is  ordinarily  about  30  times  that  fed  to 
the  boiler.  The  only  advantage  in  this  style  of  connection  is  the 
elimination  of  one  pump. 

If  a  house  pump  is  used  to  supply  the  cold  water  it  may  be  found 
better  practice  to  utilize  this  same  pump  for  supplying  water  to  the 
heater  rather  than  by  increasing  the  duty  on  the  air  pump  by 
raising  the  head. 


264  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

To  make  a  comparison  of  the  relative  economy  of  the  two 
practices  it  may  be  assumed  that  a,  in  Fig.  227,  is  5  ft.,  that  the 
condenser  uses  30  Ib.  of  water  per  pound  of  steam  condensed,  that 
the  temperature  of  the  intake  water  is  55  degrees  and  the  discharge 
water  90  degrees,  and  that  the  pump  requires  100  Ib.  of  steam  per 
horsepower.  Then  for  each  pound  of  feed  water  there  will  be 
required  the  following  additional  B.t.u.  necessary  to  raise  the 
water  5  ft.:  B.t.u.  =  (30  Ib.  X  5  ft.  X  100  Ib.  steam  per  hp.  X 
50  B.t.u.  per  Ib.  steam)  -f-  33,000  =  23.  If  cold  water  is  used, 
one-thirtieth  of  the  result  just  obtained  will  be  required  for  pump- 
ing, thus  0.75  B.t.u.  plus  the  difference  between  the  heat  units  and 
water  of  90  degrees,  or  58  B.t.u.,  and  water  of  55  degrees,  or  18 
B.tu.,  which  is  35  B.t.u.,  equals  a  total  of  35.75  B.t.u.  It  will  thus 
be  noted  that  the  cost  will  be  less  to  raise  the  entire  condensing 
water  more  than  5  ft.  (about  7  ft.  6  in.  being  the  balance)  than  to 
use  cold  injection  water.  If  more  steam  is  being  delivered  to  the 
heater  than  can  be  condensed  and  heat  units  are  thus  being  wasted, 
the  cost  of  raising  this  water  will  be  increased  twenty-two  times. 
This  is  equivalent  to  the  difference  of  elevation,  a,  being  about 
3  in.  if  all  the  steam  from  the  condenser  is  wasted. 

Under  ordinary  circumstances  the  details  shown  in  Fig.  227 
should  be  avoided,  as  this  arrangement  fails  to  provide  means  for 
supplying  water  to  the  heater  when  the  condenser  is  not  in  opera- 
tion, and  also  causes  the  air  pump  to  work  unsatisfactorily,  due  to 
the  higher  column  against  which  it  must  work. 

Class  G2  —  Heater  Water  Supply;  from  Intake.  It  is  generally 
found  necessary  to  make  a  connection  for  general  service  purposes 
from  the  intake  line  to  the  pump  suction,  two  pumps  being  used 
for  this  service.  With  such  details  no  further  provision  is  neces- 
sary to  supply  the  heater  from  the  intake.  However,  a  connection 
for  supplying  the  heater  from  the  intake  is  absolutely  necessary, 
and  if  but  one  pump  is  used  it  should  have  connections  to  both 
the  hot- well  and  the  intake.  The  condensation  pump  shown  in 
Fig.  228  (G2-i)  should  have  a  suction  line  from  the  intake  that 
can  be  used  to  supply  either  the  closed  or  open  heater  if  the  con- 
denser is  out  of  service.  This  figure  shows  the  intake  with  suc- 
tions to  the  condenser  and  the  feed  pumps.  The  feed  pump 
No.  i  ordinarily  would  be  used  for  feeding  the  boilers  and  No.  2 
would  be  the  general  service  pump.  In  regular  operation  con- 
densation pump  No.  3  would  take  the  condensation  from  the 


HEATER  WATER  SUPPLY  PIPING. 


265 


266  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

condenser  and  deliver  it  to  the  top  of  the  heater,  while  pump  No.  i 
would  take  its  suction  from  the  heater  and  No.  2  from  the  intake. 
If  the  condenser  should  be  out  of  service  then  the  suction  for  pump 
No.  3  would  be  from  the  intake  and  not  from  the  condenser.  If 
the  heater  were  out  of  service  the  condensation  would  be  delivered 
direct  to  the  suction  of  pump  No.  i,  using  the  small  well,  a,  which 
would  be  open  to  atmosphere  and  have  a  connection  to  the  con- 
denser discharge.  If  the  feed  pump  were  pumping  more  or  less 
water  than  that  delivered  to  pump  No.  3,  then  water  would  flow 
either  to  or  from  the  well  in  pipe,  b.  If  the  length  of  the  line,  6, 
is  short,  the  well,  a,  may  be  dispensed  with  by  connecting  the  lines, 
a,  b,  and  c,  and  by  having  the  line,  b,  with  its  connection  below  the 
water  level  it  will  then  be  possible  to  operate  with  the  intake  shut 
down.  To  insure  continuous  operation  these  different  connections 
as  stated  are  quite  necessary. 

Class  G3  —  Heater  Water  Supply;  from  City  Main.  Such 
boiler  installations  as  are  dependent  upon  city  water  for  their 
feed  are  of  necessity  non -condensing  plants.  These  conditions 
suggest  that  the  heater  used  should  be  of  the  open  type,  thus 
reducing  the  cost  of  water  below  that  for  the  closed  type.  Such 
being  the  case,  the  open  heater  can  be  fed  direct  from  the  city 
line,  using  the  float  control  as  regularly  supplied  with  heaters. 
If  the  plant  is  ordinarily  supplied  with  water  other  than  that 
from  the  city  mains  and  yet  the  city  water  is  available,  .it  will  be 
found  advisable  to  have  the  city  connection  to  the  heater  supply 
line  which  can  be  used  when  necessary. 

To  provide  this  connection  without  running  a  special  line  some 
plants  use  a  hose  valve  at  the  heater  inlet,  and  whenever  it  is 
necessary  to  use  city  water  the  fire  hose  is  connected  from  this 
valve  to  some  convenient  point  in  the  fire  or  other  systems  using 
city  water  and  the  heater  thus  temporarily  supplied  through  the 
hose.  This  may  seem  to  be  a  rather  crude  arrangement,  but  it 
has  the  advantage  that  the  operator  must  go  to  some  trouble  to 
make  the  hose  connections,  and  whenever  he  is  using  city  water 
the  fact  is  conspicuously  evident.  On  the  other  hand,  if  an 
operator  knows  that  he  can  get  city  water  by  simply  opening  a 
valve  it  is  not  likely  that  he  will  be  as  careful  in  keeping  his  own 
water  supply  in  good  working  order.  If  wastefulness  is  made 
easy  in  a  boiler  plant  this  fact  will  invariably  be  taken  advantage 
of,  and  for  this  reason  many  conveniences  and  precautionary 


HEATER   WATER  SUPPLY  PIPING. 


267 


devices  have  been  removed  in  such  plants  for  the  purpose  of 
avoiding  their  abuse  by  the  employees. 

Class  G4  —  Heater  Water  Supply;    from  Low-Pressure  System. 

The  regular  supply  for  open  heaters  used  in  non-condensing 
plants  having  their  own  water  supply  such  as  a  well  or  stream, 
is  taken  from  the  low-pressure  system.  The  same  pump  that 
raises  the  water  for  the  low-pressure  system  ordinarily  dis- 
charges into  a  low-down  service  tank  which  is  placed  at  a  suf- 
ficient height  to  supply  the  heater.  As  the  pressure  on  the 
low-pressure  system  is  ordinarily  quite 
low,  possibly  five  pounds,  this  makes  it 
necessary  to  use  plumbing  fixtures  of  a 
comparatively  large  size.  The  higher 
the  tank  is  placed  the  greater  will  be 
the  steam  loss  in  raising  the  water  to 
this  tank,  as  practically  all  the  water  is 
used  for  boiler  feed. 

If  it  is  necessary  to  have  a  high  tank 
for  fire  service  it  will  be  more  econom- 
ical as  regards  the  use  of  steam  for 
pumping  to  install  two  tanks,  one  at 
an  elevation,  say  100  ft.  above  grade, 
and  the  other  at  an  elevation  of  12  ft. 
above  grade.  Such  an  arrangement  is 
shown  in  Fig.  229  (G4~i).  The  same 
pump  may  be  used  to  supply  both  tanks, 
making  use  of  a  float-operated  valve,  a, 
for  the  lower  tank  and  a  check  valve, 
b,  in  the  discharge  to  the  higher  tank. 
The  valve,  a,  should  be  full-open  or 
full-closed,  allowing  the  free  travel  of 
the  float  on  its  rod.  With  such  con- 
nections when  the  valve,  a,  is  open  the 
high  head  will  at  once  be  taken  off 
the  pump  discharge  and  kept  off  until  the 
lower  tank  is  full  and  the  valve  again 

closed.  Then  the  pump  will  slow  down  and  discharge  its  surplus 
into  the  higher  tank,  the  check  valve,  b,  opening  and  allowing 
the  water  to  pass.  With  the  tanks  thus  arranged  the  pump 
could  be  so  regulated  that  it  would  supply  about  the  amount 


'"SSSSSSS/////////// 

'//////// 

1 

\ 

1 

\ 

1 

V  ! 

^ 

1 

FIG.  229  (04-1). 


268  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

of  water  required  for  boiler  feeding  and  not  discharge  to  the 
higher  tank  more  than  five  per  cent  of  the  water  raised.  Valve, 
c,  can  be  placed  in  the  high-pressure  line  to  permit  drawing 
off  part  of  the  water  in  the  upper  tank  in  case  it  becomes 
too  full. 

The  lower  one  of  the  tanks  can  be  used  for  reserve  boiler- 
feed  water,  and  should  be  made  much  larger  than  the  upper  tank, 
with  the  suction  to  the  pump  so  arranged  that  water  can  be  fed 
to  the  fire  main,  thus  fully  utilizing  the  water  from  both  tanks 
and  not  requiring  the  expenditure  necessary  to  make  a  structure 
for  supporting  all  the  water  at  the  higher  elevation. 

However,  if  the  tower  is  arranged  to  store  all  the  water  at  the 
high  elevation,  then  an  open  heater  should  not  be  used.  A 
closed  heater  may  be  placed  either  in  the  line  from  the  tank  to 
the  pump  or  from  the  pump  to  the  boilers,  less  pressure  being 
placed  upon  the  heater  if  it  is  connected  between  the  tank  and 
the  pump.  If  a  closed  heater  is  used  the  full  amount  of  head 
on  the  feed-pump  suction  is  utilized  and  the  work  imposed  upon 
the  pump  that  much  reduced.  Since  the  installation  considered 
would  be  non-condensing  with  a  surplus  of  exhaust  steam  there 
should  be,  as  regards  heat  units  transmitted  to  the  water,  no 
perceptible  loss  if  a  closed  heater  is  used,  providing,  of  course, 
that  the  heating  surface  of  the  heater  is  ample. 

Class  G5  —  Heater  Water  Supply;  from  Special  Pumps. 
Referring  to  Fig.  225  (Gi-i)  it  will  be  noted  that  a  special 
pump  is  provided  for  supplying  the  open  heater  from  the  hot- 
well  of  the  jet  condenser.  If  the  plant  has  more  than  one  con- 
denser and  more  than  one  pair  of  centrifugal  pumps  it  is  quite 
probable  that  water  for  the  heater  will  be  available  at  all  times. 
If  it  is  necessary  to  operate  non-condensing  for  a  part  of  the 
time  it  will  be  found  advisable  to  use  a  separate  drive  for  the 
heater  supply  pump  and  arrange  the  connections  so  that  this 
pump  can  take  suction  from  the  intake  as  well  as  the  hot-well. 
The  independent  condenser  pump  No.  3  in  Fig.  228  is  so 
arranged  and  permits  the  use  of  the  heater  at  all  times,  which  is 
a  very  essential  requirement. 

Instead  of  using  a  power-driven  pump,  as  shown  in  Fig.  225, 
the  heater  supply  pump  may  be  operated  in  unison  with  the  boiler- 
feed  pump,  as  shown  in  Fig.  230  (05-1).  The  feed  pump 
illustrated  is  a  regular  pattern  ram-type  pump  with  a  connecting 


HEATER   WATER  SUPPLY  PIPING. 


269 


boss,  a,  so  designed  that  the  independent  heater  pump  drive  may 
be  dropped  into  it.  The  cylinders,  6,  are  for  the  low-pressure 
heater  supply,  and  adjustable  lock  nuts,  c,  are  placed  at  the  end 
of  the  piston  rod  to  regulate  the  travel  at  d.  In  designing  the  pump 
the  piston  in  the  cylinder,  6,  would  be  made  a  trifle  larger  than 
that  of  the  feed  pump,  and  by  observing  the  overflow  of  the  heater 
the  stroke  can  be  regulated,  reducing  it  by  increasing  the  lost 


FIG.  230  (05-1) 

travel,  d,  by  running  the  lock  nut,  c,  toward  the  end.  In  this  way 
the  overflow  can  be  reduced  to  a  very  slight  amount,  which  is 
just  sufficient  to  run  off  any  oil  that  may  lie  on  top  of  the  water 
in  the  heater.  The  joint,  e,  permits  disconnecting  the  pumps,  b, 
when  the  heater  is  out  of  service,  thus  enabling  the  feed  pump 
to  take  water  from  the  hot-well  direct. 

This  system  of  pumping  water  to  the  heater  requires  no  auto- 
matic devices  for  its  regulation,  the  supply  pump  having  practi- 
cally the  same  capacity  as  the  feed  pump.  The  economy  is 
increased  as  the  duty  of  this  light-running  pump  is  put  upon 
the  heavy-service  pump,  being  equivalent  to  raising  the  water 
pressure  in  the  high-pressure  pump  about  ten  pounds  above  that 
which  would  ordinarily  be  carried. 

Class  G6  —  Heater  Water  Supply ;  from  Injection  to  Surface 
Condenser.  It  is  the  usual  custom  for  surface  condenser  manu- 
facturers to  furnish  as  a  part  of  the  condenser  equipment  the 
connection,  &,  shown  in  Fig.  226  (Gi-2).  This  connection 
with  its  valve  offers  a  passage  from  the  circulating  water  space 
to  the  vacuum  chamber  of  the  condenser.  Unless  the  valve,  b, 
can  be  so  located  that  it  is  convenient  for  the  boiler-room  operator, 
it  will  be  found  advisable  to  obtain  water  for  the  heater  in  some 
other  way,  possibly  by  taking  it  from  the  fire-pump  suction  through 


2/O  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

a  conveniently  located  regulating  valve  and  discharging  it  into  the 
condenser. 

The  heater  supply  connection  should  be  used  for  handling  only 
small  amounts  of  water,  because  if  the  steam  condensed  is  only 
a  comparatively  small  part  of  that  generated,  the  addition  of  a 
large  amount  of  water  will  unnecessarily  increase  the  work  of  the 
condensation  pump.  If  it  is  necessary  to  add  water  in  larger 
quantities  such  additional  water  should  be  delivered  direct  to  the 
heater  either  from  the  low-pressure  system  or  some  other  available 
source. 

It  is  often  found  advisable  to  neglect  a  small  loss  rather  than 
to  provide  a  more  complicated  system  which  may  be  somewhat 
more  economical. 


CHAPTER    XVII. 
LOW-PRESSURE    WATER    PIPING. 

Class  HI  —  Low-Pressure  Water;  Main.  Unless  the  plant  be 
of  smaller  capacity  than  100  or  200  hp.  a  low-pressure  water  main 
is  usually  provided  in  station  piping.  It  is  quite  essential  in  the 
larger  plants  to  have  a  low-pressure  supply  other  than  that 
afforded  by  the  city  water  mains.  About  the  only  use  for  which 
city  water  is  essential  is  for  drinking  purposes. 

If  the  plant  is  operated  condensing  the  intake  water  will  be 
found  suitable  for  the  low-pressure  service.  The  use  of  discharge 
water  for  this  service  is  quite  unsatisfactory  for  many  of  the  pur- 
poses to  which  the  water  is  put.  Discharge  water  is  suitable  for 
filling  and  washing  boilers,  for  wetting  down  ashes  and  for  similar 
services,  but  if  there  is  a  supply  needed  for  water-cooled  jackets, 
engine  journals,  dry-vacuum  pumps,  etc.,  injection  water  will  be 
found  more  suitable. 

In  considering  the  details  of  low-pressure  water  mains  there 
are  many  features  to  be  taken  into  account.  Water  should  be 
available  at  all  times  for  the  system  of  piping  which  is  always  at 
low  pressure.  There  should  also  be  available  water  for  cleaning 
boiler  tubes  with  turbine  cleaners,  this  service  requiring  a  high 
pressure.  Water  for  fire  lines  must  always  be  available  at  a  fairly 
high  pressure,  say  125  lb.  per  sq.  in.  To  permit  the  continuous 
use  of  low-pressure  water  at  about  15  lb.  pressure  it  is  necessary 
to  have  either  a  pump  on  the  service  at  all  times  or  to  use  a  storage 
tank.  A  very  satisfactory  arrangement  is  had  by  using  two  feed 
pumps  arranged  so  that  one  can  supply  the  feed  main.  No 
water  should  be  taken  from  this  pump  for  any  other  service.  When 
not  in  reserve  as  a  feed  pump  the  second  pump  should  supply 
water  for  tube  cutting. 

With  this  arrangement  the  fire  pump  would  be  on  the  fire  and  - 
the  low-pressure  systems,  maintaining  low  pressure  on  all  lines, 
and  a  tank  would  supply  water  for  the  plumbing  fixtures  and  only 
such  few  services  as  the  high  pressure  would  injure.     All  low- 

271 


2/2  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

pressure  hose  lines  could  be  taken  from  the  fire  main  and  the  pres- 
sure be  regulated  with  hose  valves  for  such  rare  cases  as  those 
when  the  fire  lines  would  be  under  heavy  pressure.  This  arrange- 
ment will  enable  the  use  of  the  entire  fire  system  for  general  hose 
service  and  give  the  fire-pump  a  continuous  light  duty.  The 
low-pressure  system  can  be  made  of  standard  fittings,  but  some 
provision  should  be  made  to  protect  this  line  against  the  possibility 
of  high  pressure  such  as  would  be  the  case  when  changing  the  set 
of  the  governor  on  the  fire  pump.  This  precautionary  measure 
might  be  accomplished  by  using  a  pressure-reducing  valve  and 
relief  valve. 

Class  H2  —  Low-Pressure ;  from  Pump.  The  low-pressure 
pump  should  have  a  governor  that  can  quickly  be  set  for  high  or 
low  pressure;  this  can  be  accomplished  by  using  a  weight  that 
can  be  removed  in  one  piece,  so  that  the  high  pressure  and  the 
low  pressure  are  fixed  by  the  handling  of  the  single  weight.  The 
advantage  of  this  arrangement  is  that  when  the  fire  pump  is 
supplying  the  low-pressure  water  the  simple  movement  of  chang- 
ing the  weight  will  put  the  pump  on  the  fire-main  service  with- 
out handling  any  valves. 

Class  H3  —  Low-Pressure  Water;  to  and  from  Water-Tank. 
The  most  convenient  arrangement  for  a  water  tank  is  to  place 
it  between  the  trusses  in  the  engine  room  and  support  it  as 
shown  in  Fig.  231  (H^-i).  An  iron  tank  located  as  shown 
and  open  to  the  engine  room  is  very  objectionable  on  account  of 
its  "sweating."  The  high  temperature  of  the  engine  room  admits 
of  the  carrying  a  large  amount  of  moisture,  this  being  gov- 
erned by  the  amount  of  escaping  steam  and  by  weather  conditions. 
The  moisture  in  the  air  is  so  readily  condensed  on  the  sides  of 
the  cool  water  tank  that  the  outer  surfaces  of  such  tanks  are 
usually  quite  wet.  This  causes  much  trouble  from  dripping. 
When  a  tank  is  not  wet  and  dripping  it  exposes  ?,  badly  dis- 
figured surface  due  to  its  former  sweating.  Placing  the  tank  in 
the  boiler  room  only  adds  to  the  difficulties  by  the  water  in  the 
tank  taking  up  boiler-room  dust. 

Another  method  of  supporting  the  tank  is  to  place  it  on  a 
division  wall  over  the  top  of  the  roof.  This  is  a  troublesome 
arrangement  in  many  ways;  the  pipes  to  the  tank,  also  the  tell- 
tales, etc.,  must  be  run  through  the  roof,  the  openings  for  which 
afford  opportunities  for  leaks.  With  a  tank  so  placed  it  would 


LOW  PRESSURE   WATER  PIPING. 


be  necessary  in  extremely  cold  weather  to  make  some  provision 
against  freezing. 

A  wooden  tank  would  be  quite  as  objectionable,  if  not  more  so, 
than  an  iron  one.  Such  tanks  do  not  sweat,  but  it  is  next  to 
impossible  to  keep  them  tight  in  such  a  hot  place  as  the  upper 


FIG.  231  (H3-i). 

part  of  an  engine  room.  Probably  the  most  satisfactory  tank 
for  such  a  location  as  shown  in  Fig.  231  is  a  box  of  matched 
lumber  sufficiently  strong  to  hold  the  water  and  lined  throughout 
with  sheet  copper  having  well-soldered  joints.  Such  a  tank  will 
be  found  as  easy  to  make  tight  as  an  iron  one  and  no  difficulty 
will  be  experienced  from  dripping. 

Another  method  of  overcoming  the  trouble  from  dripping  is 
to  enclose  the  tank  in  a  "room"  between  the  trusses,  using,  if 
desired,  a  metal  floor  and  the  partition,  a,  shown  dotted  in 
Fig.  231.  This  room  may  also  have  windows  opening  to  the  out- 
side of  the  building.  By  the  use  of  such  a  room  the  engine-room 
air  is  prevented  from  coming  in  contact  with  the  tank  and  by 
manipulating  the  windows  the  air  around  the  tank  can  be  kept 
at  a  low  temperature,  thus  permitting  the  use  of  a  plate-iron  tank 
without  the  difficulties  previously  mentioned. 

There  are  three  methods  for  supplying  such  tanks  with  water. 


274 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


The  first  is  by  the  use  of  a  float  and  lever  connected  to  the  steam 
pipe  of  the  pump  (or  an  electrical  controlling  device).  The 
second  is  by  the  use  of  a  float  and  lever  arranged  to  operate  the 
water  valves  in  the  line  discharging  into  the  tank.  The  third  is 
by  means  of  a  float,  pulleys  and  tell-tale  placed  on  the  wall  so 
that  the  operator  can  see  and  control  the  feeding  arrangement 


FIG.  232  (H3-2). 

by  hand.  There  should  be  an  overflow  emptying  either  into  a 
funnel  in  a  conspicuous  place  or  in  such  a  manner  as  to  attract 
the  notice  of  the  operator. 

The  float  control  of  steam  valves  is  the  most  satisfactory 
method  of  regulation,  if  the  pump  can  be  kept  constantly  in  use 
for  this  particular  service.  This  requirement  can  generally  be 
arranged  for,  as  there  are  only  two  water  services  regularly  needed 
for  station  use;  boiler  feed  and  general  water  supply,  as  shown 
in  Fig.  232  (H3-2).  With  the  arrangement  as  shown  the 
auxiliary  main  would  be  under  low  pressure  and  would  be  con- 
nected with  the  pump  discharging  into  the  tank;  in  fact  it  would  be 


LOW  PRESSURE   WATER   PIPING.  2? 5 

supplied  from  the  tank.  It  will  be  noted  that  the  low-pressure 
main  is  in  no  way  connected  with  other  lines  that  at  times 
carry  high  pressures.  Thus  the  arrangement  avoids  the  possi- 
bility of  water  under  high  pressure  being  let  into  the  low-pressure 
system.  The  pumps  are  shown  with  each  having  similar  con- 
nections for  suction,  discharge  and  steam  openings.  This  allows 
the  use  of  either  pump  for  boiler  feeding,  and  the  selection  of  the 
pump  which  is  in  the  best  condition  for  use  in  boiler  feeding 
while  the  other  is  used  for  tank  work. 

The  use  of  a  float  for  operating  the  water  valve  offers  many 
desirable  features  and  simplifies  operation  duties.  The  pump 
discharge,  a,  shown  dotted  in  Fig.  232  is  carried  to  the  top  of  the 
tank  and  connected  with  a  float  which  in  turn  controls  the  dis- 
charge. With  the  discharge  so  arranged  the  steam  is .  carried 
direct  from  the  main  to  the  pump  which  has  a  governor  that  can 
be  set  for  a  suitable  pressure  sufficiently  in  excess  of  the  tank 
pressure  to  insure  raising  the  water  to  the  tank  level. 

As  long  as  the  fire  main  is  kept  under  about  the  same  pressure 
as  that  supplied  by  the  tank  there  will  be  but  little  wear  at  the 
float  valve  on  the  end  of  the  pipe,  a.  However,  if  the  difference 
in  pressure  is  considerable  some  special  provision  should  be 
made  so  that  the  float  valve  will  not  cut  out  its  faces.  The  most 
serviceable  arrangement  to  meet  these  requirements  includes 
provisions  for  allowing  the  float  a  considerable  range  of  travel, 
so  that  when  the  float  is  close  to  the  bottom  of  the  tank  the  valve 
will  be  fully  open  and  when  the  water  is  near  the  overflow  point 
the  valve  will  be  fully  closed,  having  no  intermediate  position. 

Fig-  233  (113-3)  illustrates  a  valve  so  constructed  and  includ- 
ing in  its  design  a  small  waste  valve  attached  to  the  float  together 
with  a  piston-operated  valve  for  regulating  the  flow  of  water  to 
the  tank.  In  this  device  when  the  main  valve  is  open  the  waste 
valve  is  also  open;  the  free  travel  in  the  valve  stem,  a,  allows  the 
float  to  take  the  extreme  range  before  the  valve  is  operated. 

When  the  supply  tank  is  fitted  with  a  tell-tale  and  has  a  suffi- 
cient capacity  for  many  hours'  service  it  is  common  practice  to 
use  a  hand-control,  either  starting  or  stopping  the  pump  that 
supplies  the  tank  or  by  throttling  the  water  supply  to  the  tank  if 
the  main  from  which  it  is  supplied  is  constantly  under  pressure. 

Another  method  of  storing  water  and  one  especially  suited  for 
pressures  higher  than  those  obtained  by  the  use  of  a  gravity  tank, 


276 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


employs  an  expansion  air  tank.  This  tank  may  be  placed  in  the 
basement,  and  if  the  station  is  equipped  with  an  air  compressor 
the  larger  portion  of  the  tank's  volume  may  be  utilized  for  storing 
water.  For  example,  if,  at  any  time,  the  tank  be  three-fourths 
full  of  water  at  75  Ib.  pressure  and  then  be  emptied  of  the  water, 


FIG.  233  (H3-3). 

there  will  be  a  pressure  of  7  Ib.  per  sq.  in.  when  the  water  has  been 
discharged,  these  pressures  being  considered  as  above  atmospheric 
value. 

To  assure  the  maintenance  of  a  fairly  even  pressure  it  is  neces- 
sary that  an  expansion  tank  be  quite  large,  even  though  the  quan- 
tity of  water  to  be  withdrawn  at  any  one  time  is  relatively  small. 
To  obtain  an  allowable  pressure  drop  of  10  Ib.  with  the  tank 
earlier  mentioned  as  carrying  75  Ib.  pressure,  there  would  be 
required  a  cubical  contents  of  36  cu.  ft.  for  each  cubic  foot  of 
water  to  be  withdrawn. 

A  pressure  tank  is  especially  useful  in  connection  with  a  pump 
doing  constant  service  and  under  the  control  of  a  governor;  the 
tank  allows  the  pump  gradually  to  increase  and  decrease  its  dis- 
charge without  sudden  pressure  changes  and  the  consequent 
shocks.  A  gravity  tank,  however,  is  more  satisfactory  for  power- 
plant  uses  than  a  pressure  tank,  because  the  air-pressure  tank  is 
under  more  severe  stress  than  any  other  part  of  the  water  system, 
while  a  gravity  tank  is  under  the  least  pressure  of  any  part  of  its 


LOW  PRESSURE   WATER  PIPING.  2// 

system.  The  expense  of  supporting  a  gravity  tank  is  much  less 
than  the  original  cost  for  building  a  larger  tank  which  must  with- 
stand higher  pressure. 

As  a  gravity  tank  is  quite  essential,  provision  should  be  made 
for  its  accommodation  when  the  structural  work  is  designed.  The 
cost  of  installation  will  thus  be  reduced  materially.  Ordinarily 
it  will  be  found  the  cheaper  method  to  allow  the  contractor  for  the 
structural  steel  to  furnish  the  tank,  tank-room  floor,  partitions  and 
such  ladders  as  may  be  required  to  reach  the  tank  room.  In 
designing  the  building  walls,  if  a  traveling  crane  is  used  which  will 
run^close  to  the  face  of  the  wall,  a  chase  should  be  left  to  accommo- 
date the  piping  for  the  water  supply  to  the  tank,  and  for  an  over- 
flow and  possibly  a  separate  discharge  pipe. 

Class  H4  —  Low-Pressure  Water;  to  Heater.  Ordinarily  it 
will  not  be  found  good  practice  to  supply  low-pressure  water  to  an 
open  heater  since  the  low-pressure  service  is  generally  cold  water 
and  at  pressures  in  the  neighborhood  of  15  Ib.  If  the  plant  is  of 
the  condensing  type  other  means  are  possibly  available.  If  the 
plant  is  of  the  non-condensing  type  a  loss  will  be  occasioned  by 
pumping  the  supply  water  against  a  2O-lb.  pressure  and  discharg- 
ing it  to  atmospheric  pressure. 

Under  these  conditions  if  the  plant  being  considered  has  3,000 
hp.  of  boiler  capacity  there  will  be  about  90,0x30  Ib.  of  water  raised 
about  40  ft.  higher  than  necessary,  or  a  loss  equivalent  to  3,600,000 
ft.  Ib.  per  hr.,  which  equals  60,000  ft.  Ib.  per  min.,  or  2  hp. 
If  the  pump  m  uses  100  Ib.  of  steam  per  hp.  hour  the  loss 
would  then  be  200  Ib.  of  steam  per  hour.  This  extra  work  would 
require  about  30  Ib.  of  coal  per  hr.  or  720  Ib.  per  day  of  24  hr. 
and  at  $2.00  per  ton  or  .1  cent  per  pound  the  loss  will  be  72  cents 
per  day  or  $262.80  per  year;  thus  an  investment  of  more  than 
$1,500  will  be  justified  to  save  this  loss.  Such  an  amount  is  more 
than  sufficient  to  cover  the  cost  of  any  device  necessary  for  the 
purpose.  If  the  plant  is  non-condensing  and  can  use  all  the 
exhaust  from  the  pump  in  the  heater,  then  the  steam  loss  would 
be  much  less,  but  the  loss  by  the  use  of  cold  water  rather  than 
condenser  discharge  water,  would  bring  about  still  another  loss. 

For  a  'non-condensing  plant  the  arrangement  shown  in  Fig.  230 
(05-1)  is  simple  and  economical,  using  as  it  does  the  heater 
supply  pump  connected  with  the  feed  pump.  It  is  safe  to  assume 
that  the  ordinary  float  with  the  float-controlled  valve  as  furnished 


2/8  STEAM   POWER   PLANT  PIPING   SYSTEMS. 

with  open  heaters,  will  require  as  much  attention  and  cause  as 
much  annoyance  as  the  low-duty  water  cylinders  added  to  the  feed 
pump.  If  there  is  but  one  feed  pump  with  its  heater  pump  attached 
then  it  will  be  advisable  to  run  a  branch  from  the  low-pressure 
main  to  the  heater.  This  branch  can  be  used  in  case  of  repairs 
such  as  would  necessitate  shutting  down  the  heater  pump.  The 
saving  that  may  be  secured  during  such  short  intervals  will  not  pay 
for  the  investment  in  a  reserve  heater  pump. 

Class  H5  —  Low-Pressure  Water;  to  Engine  Journals.  Many 
of  the  large  engines  are  provided  with  hollow  journal  shells  and 
arranged  for  passing  water  through  these  chambers  to  carry  off 
the  heat  generated  by  friction.  If  a  large  quantity  of  oil  could  be 
circulated  through  such  journals  and  caused  to  pass  over  the  hot 
surfaces,  it  would  accomplish  the  same  result.  This  procedure, 
however,  is  impossible  as  the  weight  of  the  moving  parts  sliding  in 
the  journal  prevents  more  than  a  film  of  oil  passing  over  the  sur- 
face which  requires  cooling.  The  water  chamber  is  not  similarly 
restricted,  the  volume  that  can  be  passed  over  its  hot  surfaces  being 
determined  by  the  size  of  the  connections  and  the  water  pressure. 
The  inability  of  oil  to  cool  journals,  even  when  fed  in  a  stream,  is 
fully  demonstrated  in  the  cases  of  hot  bearings  that  necessitate 
shutting  down  the  engine  and  cooling  the  journals  before  again 
starting.  However,  these  same  journals  after  starting  up  may 
continue  to  run  cool  with  an  ordinary  supply  of  oil. 

The  lower  sections  of  the  main  journals  are  the  only  bearings 
that  ordinarily  are  water  cooled.  These  bearings  lie  in  close 
contact  with  the  shaft  at  all  times,  thus  preventing  a  free  supply 
of  oil  to  their  sliding  faces.  The  side  cheeks  and  caps,  also  the 
crank  and  cross-head  pins  are  in  close  contact  only  part  of  the  time, 
which  permits  oil  to  flow  between  their  faces  every  time  the  piston 
reciprocates. 

In  designing  a  water-cooling  system  for  journals  considera- 
tion should  be  given  so  that  the  pipe  connections  will  be  free  to 
expand  and  contract  at  the  connections  with  the  journal.  This 
allowance  is  not  on  account  of  heat,  but  on  account  of  the  move- 
ment of  the  lower  shell.  If  the  side  cheeks  are  quite  free  from 
the  shaft  it  will  move  crossways  in  the  bearing  and  cause  the 
bearing  to  move  also.  This  movement  cannot  be  taken  up  com- 
pletely or  the  journal  will  heat,  but  it  should  be  reduced  to  the 
least  possible  amount,  thus  retaining  the  lower  bearing  in  a  form 


LOW  PRESSURE   WATER   PIPING.  279 

that  will  correspond  to  that  of  the  shaft.  There  is  sure  to  be 
some  pounding  in  the  journal  and  this  continual  jar  will  break 
pipe  connections.  The  nipple  and  possibly  the  next  piece  of 
pipe  away  from  the  journal  should  be  extra  heavy  and  if  the 
opening  in  the  journal  is  large  it  will  be  found  advisable  to  reduce 
the  diameter  of  the  pipe  at  the  first  elbow  to  a  size  smaller  than 
the  regular  line  to  the  journal. 

Fig.  234  (H5-i)  shows  a  very  satisfactory  construction  with 
pipe  connections  entirely  outside  of  the  frame,  thus  avoiding 
the  possibility  of  their  being  strained  against  the  frame  of 
the  engine.  As  shown  they  are  also  exposed  to  view  which  is 
advantageous  in  case  of  leaks.  The  water  can  be  diverted  over 
the  surface  of  the  journal  either 
by  means  of  dividing  partitions 
cast  in  the  journal  or  by  a  pipe 
run  into  the  journal  and  forming 
one  of  the  connections.  The 
regulating  valve  should  be  on 
the  inlet  branch,  the  outlet  being 
free  to  atmosphere  and  discharg- 
ing into  a  funnel  that  may  readily 
be  seen  and  tested  by  the  oper- 
ator. To  allow  the  greatest  FIG.  234  (HS-I). 
possible  flexibility  the  supports 

for  the  piping  should  be  well  away  from  the  journal.  The 
discharge  should  be  carried  to  a  height  slightly  above  the 
journal,  thus  assuring  that  the  bearing  will  at  all  times  be  full 
of  water. 

Class  H6  —  Low-Pressure  Water ;  to  Dry- Vacuum  Pump.  For 
continuous  running  it  is  absolutely  necessary  to  cool  the  air  cylin- 
der of  the  dry-vacuum  pump.  Low-pressure  water  is  used  for 
this  purpose.  The  temperature  of  the  air  pumped  is  generally 
about  120°  F.,  and  if  no  air  cooler  is  used  and  air  is  compresse  1 
from  about  2  Ib.  absolute  to  15  Ib.  it  is  thus  reduced  to  about 
one-seventh  of  its  former  volume.  The  dry-vacuum  pump 
will  operate  under  rather  high  temperatures,  thus  permitting 
cooling  water  to  be  discharged  at  a  temperature  as  high-  as  175°  F. 
The  arrangement  of  pipes  for  cooling  the  journal,  as  shown  in 
Fig.  234,  is  also  suitable  for  cooling  an  air-pump  cylinder,  using 
only  the  inlet  valve  to  control  the  water  and  an  open  funnel  to 


280  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

observe  the  quantity  and  temperature.  The  amount  of  cooling 
water  necessary  to  reduce  the  temperature  of  the  air  cylinder  of 
the  dry-vacuum  pump  is  quite  small,  being  only  about  1.5  per 
cent  of  that  used  for  boiler  feeding.  The  amount  of  water  so 
used  should  be  determined  by  observation  of  the  condition  of 
the  pump  at  various  temperatures  of  the  cooling  water. 

One  of  the  most  frequent  troubles  with  air  cylinders  is  brought 
about  by  the  admitting  of  oil  to  the  cylinder,  which,  due  to  the 
high  temperature,  becomes  burned  onto  the  air-discharge  valve. 

Class  H7  —  Low-Pressure  Water;  to  Pump  Priming  Pipes.  A 
low-pressure  water  connection  should  always  be  provided  for 
priming  fire  pumps.  This  connection  is  not  installed  because 
such  pumps  are  not  capable  of  lifting  water  without  priming, 
but  because  the  pump  priming  pipes  connected  with  the  low- 
pressure  water  main  enable  the  fire  pump  to  discharge  water 
and  be  in  service  for  full  duty  in  the  least  possible  time.  As 
the  saving  in  time  in  priming  feed  and  ordinary  service  pumps  is 
not  as  essential  as  with  fire  pumps  they  are  seldom  equipped 
with  priming  pipes.  The  piping  arrangement  shown  in  Fig. 
216  (Fi~3)  will  be  found  satisfactory  for  the  service  pump. 
A  fire  pump  should  have  a  foot  valve,  also  a  priming  connection 
between  the  suction  and  discharge  valves  at  both  ends  of  the 
pump  and  should  also  have  priming  connections  to  the  suction 
line.  By  the  use  of  these  several  details  air  may  be  removed 
from  the  pump  before  it  is  started.  If  priming  water  is  not  easily 
obtainable  from  a  low-pressure  line  or  from  the  pump  discharge 
as  shown  in  Fig.  216,  then  a  hose  valve  should  be  attached  to  the 
pump  between  the  suction  and  discharge  valves  at  all  four  ends 
of  a  double-acting  pump.  This  detail  can  be  satisfactorily 
arranged  by  connecting  the  four  ends  with  piping  and  using 
check  valves  that  open  into  the  ends  of  the  cylinders  and  a  stop 
valve  to  control  the  water  from  the  hose  or  pipe  line. 

The  usual  method  of  freeing  a  pump  of  air  is  to  close  the  valves 
in  the  discharge  and  open  the  vent  over  the  discharge  pump 
valve,  thus  allowing  the  contents  of  the  cylinder  to  be  discharged 
to  atmosphere  at  a  low  pressure.  All  the  air  can  in  this  way  be 
discharged  from  the  pump  if  the  priming  water  is  admitted 
between  the  suction  and  the  discharge  valves.  Such  an  arrange- 
ment of  valves  requires  a  large  air  vent,  and  if  a  check  valve 
is  placed  in  the  discharge  line  from  the  pump  it  will  prevent  the 


LOW  PRESSURE   WATER  PIPING.  28 1 

pressure  coming  back  on  the  pump  valve  whenever  the  air  relief 
is  open. 

The  usual  boiler-room  operator  is  not  sufficiently  skilled  to 
handle  these  priming  arrangements  unless  they  are  quite  simple. 
To  free  a  pump  of  air  when  it  is  not  fitted  with  priming  pipes 
requires  even  more  skill.  Any  operator  should  quickly  learn  to 
open  the  air  vent  and  admit  priming  water  if  that  is  all  that  is 
required.  It  must  not  be  inferred  that  priming  pipes  are  mere 
conveniences,  since  there  are  many  installations  in  which  they  are 
absolutely  essential  and  with  which  if  priming  pipes  were  not 
supplied  it  would  be  necessary  when  priming  to  open  the  pump 
and  fill  it  with  water  by  using  a  hose,  pail  or  similarly  crude  method, 
before  the  pump  could  be  put  into  operation. 

The  use  of  priming  connections  with  centrifugal  pumps  is 
indispensable,  as  has  been  explained  under  Class  C  (F-i). 
Generally  speaking,  the  priming  line  to  a  pump  has  a  diameter  of 
about  one-eighth  that  of  the  pump  suction. 

Class  H8  —  Low-Pressure  Water ;  to  Hose  Connections.  There 
are  generally  three  distinct  hose  systems  for  a  power  plant,  but 
oftentimes  one  of  these  systems  is  made  to  serve  for  another.  They 
are  the  fire  service,  the  sprinkling  and  the  regular  low-pressure 
service  as  used  for  wetting  down  ashes,  washing  floors,  etc.  For 
the  purpose  of  simplifying  piping  arrangements  these  three  services 
should  be  divided  into  two  systems  that  may,  with  safety  and 
without  causing  serious  difficulty,  be  changed  from  low  to  high- 
pressure  systems.  Ordinarily  one  system  should  supply  all  the 
hose  connections.  The  other  system  should  be  designed  without 
by-passes  or  other  means  by  which  high  pressure  could  be  put  on 
it.  The  only  hose  connections  that  should  take  their  supply  from 
the  low-pressure  system  should  be  those  for  wetting  down  ashes. 
This  class  of  work  is  better  served  by  using  water  under  low  head, 
thus  avoiding  the  dust  and  spattering  that  would  be  caused  by 
water  of  high  velocity  striking  the  ashes.  As  this  advantage  is  too 
slight  to  call  for  a  separate  pipe  line  for  wetting  down  ashes  it  will 
be  advisable,  if  the  fire  line  passes  near  the  boiler  front,  to  connect 
with  it  the  hose  for  this  service,  controlling  the  pressure  by  valves 
at  the  hose  connections. 

If  the  low-pressure  system  is  supplied  from  a  tank  there  should 
be  only  such  connections  taken  off  this  system  as  would  be  injured 
by  high  pressure,  but  to  avoid  running  special  lines  and  thus  com- 


282  STEAM  POWER   PLANT  PIPING  SYSTEMS. 

plicating  the  station  pipe  work  it  may  be  found  advisable  to  make 
occasional  hose  connections  with  the  high-pressure  line. 

A  simple  arrangement  for  floor  washing 
is  to  use  a  small  hose  with  a  large 
coupling  at  the  end  for  attaching  to  the  fire 
connection.  To  avoid  cutting  the  regular 
fire-service  valves  it  is  quite  necessary 
that  a  separate  valve  for  controlling  the 
water  should  be  attached  to  the  regular 
hose  valve.  If  a  hose  coupling  of  large 
size  can  be  tapped  out  of  the  fire  line  and 
a  nipple  attached  as  shown  by  a,  in  Fig. 
FIG.  235  (H8-i).  235  (H8-i),  a  very  convenient  connec- 

tion is  had.     An  alternate  method  would 

be  had  by  screwing  a  small  valve  onto  the  larger  valve  and  con- 
necting the  hose  with  the  coupling,  b. 

Class  H9  —  Low-Pressure  Water;  to  Oil  Filter  and  Tanks.  Low- 
pressure  water  service  for  washing  purposes  supplied  with  hand 
control  is  usually  provided  for  the  oil  filter  and  tanks.  A  very 
satisfactory  piping  arrangement  is  had  by  running  steam  and  low- 
pressure  water  pipes  to  an  "  ejector-tee, "  having  a  valve  in  each 
line  and  a  means  for  connecting  the  hose  to  the  tee.  With  such 
connections  water  can  be  supplied  either  hot  for  cleaning  tanks  or 
cold  for  general  use.  If  water  is  required  in  any  tank  it  can  be 
supplied  by  hose  or,  in  the  case  of  precipitating  gravity  tanks,  it 
may  be  admitted  through  pipe  connections.  Ordinarily  the  water 
required  for  this  service  does  not  exceed  that  which  may  be  delivered 
through  a  J-in.  pipe. 

Class  H10  —  Low-Pressure  Water;  to  Grease  Extractor.  Only 
a  small  amount  of  water  is  required  for  grease  extractors,  the 
quantity  being  just  sufficient  to  keep  the  baffle  plate  wet  and 
amounting  to  about  5  per  cent  of  the  steam  passing  through  the 
extractor.  A  water  connection  is  essential  for  the  successful 
operation  of  even  the  most  efficient  grease  extractors.  The  water 
admitted  to  the  separator  is  discharged  together  with  the  con- 
densation, grease,  etc.,  to  an  en  trainer.  This  en  trainer,  for  a 
vacuum  separator,  is  designed  to  receive  first,  drips  under  vacuum; 
then,  by  a  tilting  mechanism  to  close  the  drip  opening  and  open  a 
steam  connection  so  that  the  accumulated  drips  are  blown  out;  it 
then  closes  the  steam  and  opens  the  drip  connections  in  turn, 


LOW  PRESSURE   WATER   PIPING.  283 

working  in  a  manner  somewhat  similar  to  the  action  of  a  steam 
trap. 

If  the  grease  extractor  is  in  series  with  the  vacuum  line  to  the 
condenser  the  spray  water,  even  though  lifting  is  necessary,  may  be 
taken  from  the  condenser  circulating  water.  This  supply  will  be 
found  somewhat  more  reliable  than  the  low-pressure  main  and  no 
pumping  machinery  will  be  required  to  insure  its  continuous 
operation.  If  the  grease  extractor  forms  a  part  of  an  atmospheric 
exhaust  line  it  will  be  necessary  to  supply  the  spray  water  under  a 
head  greater  than  the  exhaust  pressure.  In  this  case  the  drips 
would  be  discharged  through  a  steam  trap  or  a  U-shaped  drip  loop. 

Class  Hll  —  Low-Pressure  Water;  to  Cooling  Boxes  at  Furnaces. 
There  are  some  makes  of  furnaces  that  require  water  cooling  to 
prevent  them  from  being  burned.  Such  devices  waste  the  heat 
taken  up  by  the  water,  when  it  is  discharged  to  the  sewer,  and  they 
are  a  source  of  constant  trouble.  The  manufacturers  of  station 
equipments  call  into  use  many  methods  for  eliminating  this  trouble- 
some detail.  The  reason  for  this  choice  is  not  that  they  can  secure 
better  results,  but  with  a  view  to  avoiding  the  serious  loss  and  any 
interruption  of  operation  that  would  be  caused  by  a  failure  of  the 
water  supply.  The  customary  method  of  regulating  the  supply  to 
such  devices  is  by  maintaining  full  water  pressure  on  the  parts  to  be 
cooled  and  controlling  the  water  with  a  discharge  valve.  If  the 
heat  in  the  furnace  increases  it  is  possible  to  generate  steam  and 
drive  the  water  out  of  the  water  box  unless  the  discharge  opening 
be  increased  before  the  temperature  is  raised  to  the  steaming  point. 
Thus  in  the  operation  of  such  cooling  systems  the  water  must  be 
wasted  or  a  risk  run  of  damaging  the  water  box.  By  admitting 
water  into  a  box  which  has  attained  a  high  temperature  and  driven 
out  the  water  or  in  some  other  manner  been  without  water  for  a 
short  time,  there  is  not  only  the  danger  of  burning  the  water  box, 
but  a  still  greater  one  of  cracking  it.  As  a  proof  that  much  greater 
damage  is  caused  by  cracking  than  by  burning  many  of  the  builders 
of  this  class  of  apparatus  are  now  making  water  boxes  of  riveted 
boiler  plate. 

If  a  considerable  supply  of  water  is  connected  to  a  water  box  so 
arranged  that  the  water  can  circulate  in  it  relief  will  be  had  from 
much  of  the  danger  occasioned  by  interrupted  water  supply. 
The  water  in  the  tank,  in  case  of  approaching  trouble,  would  be- 
come overheated  and  give  a  warning.  A  tank  for  this  purpose,  to 


284 


STEAM  POWER  PLAXT  PIPING  SYSTEMS. 


permit  of  circulating  water  being  at  not  less  than  210  degrees  in 
temperature,  should  be  placed  as  high  as  possible.  When  the 
heater  used  is  of  the  open  type  and  the  tank  is  placed  at  a  high 
level  the  overflow  may  be  discharged  to  the  heater. 

The  arrangement  as  shown  in  Fig.  236  (Hn-i)  has  an 
outside  water-circulating  tank  and  an  admission  valve,  a,  dis- 
charging water  through  a  syphon-tee,  thus  bringing  about  a  forced 
circulation  when  the  valve  is  open.  It  is  desirable  to  place  the 
the  storage  tank  as  high  as  possible,  thus  increasing  the  velocity 
for  circulation  and  raising  the  overflow,  6,  to  a  height  sufficient  for 
discharging  into  the  open  heater.  To  insure  the  water  passing 
over  the  entire  surface  of  the  water  box,  the  tube,  c,  is  attached  to 


j*.  c 


FIG.  236  (Hn-i). 

the  end  of  the  inlet  pipe.  To  permit  free  circulation,  the  connec- 
tions from  the  tank  to  the  water  box  should  be  of  large  size  and 
arranged  in  as  direct  a  line  as  possible.  To  prevent  the  possibility 
of  water  wasting  away  through  the  supply  pipe,  if  for  any  reason 
the  pressure  on  it  should  drop  below  that  at  the  inlet  pipe,  a  check 
valve,  d,  should  be  placed  in  the  inlet  pipe.  With  connections  as 
shown  when  the  water  becomes  very  hot  it  will  boil  in  the  tank 
and  give  sufficient  warning  to  the  operator  so  that  he  may  know 
when  to  alter  the  set  of  the  valve  a,  and  prevent  any  damage. 
To  allow  for  the  boiling  away  of  part  of  the  water  without  lowering 
its  upper  surface  below  the  inlet,  the  connection,  e,  should  be 
made  lower  than  the  outlet,  b.  Unless  this  precaution  is  taken 
when  the  water  level  is  lowered  below  e,  circulation  through  the 
water  box  will  be  entirely  stopped. 


LOW   PRESSURE    WATER   PIPING. 


285 


It  may  be  advisable  to  consider  the  merits  of  some  of  the 
devices  using  fire  tile  in  place  of  water-cooled  boxes  and  designed  to 
do  the  same  work.  The  water-cooled  parts  are  used  to  save  the 
expense  of  fire  tile  destroyed  by  the  high  temperatures  to  which 
they  are  subjected.  In  many  cases  it  costs  more  to  maintain  the 
water-cooled  part  than  to  replace  the  tile. 

Class  HIS  —  Low-Pressure  Water;  from  Economizer  to  Heating 
System.  In  many  power  plants  hot  water  serves  best  for  heating 
service.  If  there  is  available  an  abundance  of  exhaust  steam 
it  will  probably  be  good  practice  to  use  it  for  heating  the  water 
in  a  large  heater.  For  a  condensing  plant  the  heating  problem 
becomes  somewhat  more  difficult.  A  heating  system  should 
be  under  low  pressure,  which  precludes  the  use  of  water  taken 
direct  from  the  boiler. 

The  higher  the  pressure  carried  by  a  condensing  plant  the 
more  suitable  would  be  the  use  of  low-pressure  economizers; 
with  the  lower  pressures  the  strains  in  the  economizers  would  be 
comparatively  small  and  a  supply  of  water  suitable  for  heating 
would  be  available. 

In  Fig.  237  (H2i-i)  is  shown  an  economizer  arranged  for 
operation  at  low  pressure.  With  this  arrangement  pump  No.  i 


FIG.  237  (Hi2-i). 

serves  to  keep  the  economizer  under  pressure  and  discharge  hot 
water  either  to  feed  pump  No.  2  or  circulating  pump  No.  3.  By 
closing  valves  a  and  b,  the  heating  system  is  entirely  shut  off 
from  the  economizer. 

If  the  quantity  of  water  passing  through  an  economizer  is 
considerable  the  temperature  of  the  flue  gases  and  the  water  will  be 
lowered.  In  ordinary  practice  an  economizer  delivers  to  water 


286  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

passing  through  it  about  one-sixth  as  many  heat  units  as  the 
boilers,  or,  in  other  words,  it  has  about  one-sixth  the  capacity  of 
the  boiler  equipment.  By  increasing  the  quantity  of  water 
passing  through  the  economizer  the  temperature  of  the  gases  is 
lowered,  thus  increasing  the  capacity  of  the  economizer  to  possibly 
one-fourth  that  of  the  boiler  plant.  In  other  words,  an  economizer 
equipment  for  i,ooo-hp.  boiler  capacity  will  raise  the  water  for 
heating  purposes  to  a  temperature  approximating  that  which 
would  be  done  with  25o-hp.  capacity  of  independent  hot-water 
heaters. 

It  will  not  be  found  advisable  to  use  over  10  per  cent  of  the 
total  capacity  of  the  boilers  for  heating  purposes,  as  there  will  be 
times  when  only  part  of  the  boilers  are  in  operation,  and  by  using 
water  from  the  economizer  for  boiler  feeding  the  supply  capacity 
for  the  heating  system  will  also  be  decreased.  With  large  power 
plants,  say  of  5,000  boiler-hp.  capacity,  only  about  3  per  cent  of 
the  output  will  be  required  for  heating,  possibly  150  hp.,  and 
this  duty  can  readily  be  performed  by  the  economizer  with  no 
perceptible  change  in  water  or  flue-gas  temperatures.  The 
efficiency  of  a  heating  system  so  arranged  would  even  be  higher 
than  that  of  a  steam  plant  not  having  a  heating  system  in  connec- 
tion with  its  economizers,  since  the  arrangement  as  suggested  would 
utilize  heat  that  otherwise  would  be  wasted. 

Class  H13  —  Low-Pressure  Water;  to  Plumbing  Fixtures.  In 
nearly  all  power  plants  both  hot  and  cold  water  are  required  for 
the  plumbing  fixtures  and,  therefore,  a  low-pressure  supply  is 
necessary  for  this  service.  The  light  float  valves  furnished  with 
water  closets,  basin  cocks,  etc.,  are  only  suitable  for  low  pressures 
of  about  20  Ib.  There  valves  operate  well  on  much  lower  pressures, 
but  under  such  conditions  for  pressures  of  about  5  Ib.  require 
somewhat  larger  lines. 

If  a  low-pressure  water  tank  forms  a  part  of  the  power  plant 
piping  system  the  cold-water  service  should  be  taken  from  this 
supply.  Water  would  then  be  available  for  closets  and  wash- 
bowls, even  though  the  pumps  were  in  use  for  other  service.  If 
only  a  small  quantity  of  low-pressure  water  is  required,  say 
500  gal.  per  day,  it  may  be  advisable  to  use  city  water  if  it  is 
available.  It  must  also  be  remembered  that  as  the  quantity  of 
water  required  is  reduced  the  size  and  cost  of  the  necessary 
storage  tank  and  its  supports  are  also  reduced  in  direct  proportion. 


LOW  PRESSURE  WATER  PlPlXG.  287 

For  supplying  such  small  tanks  the  feed  pump  may  be  shut  off  from 
the  boilers  long  enough  to  allow  the  tank  to  be  filled  once  a  day. 

The  supply  of  hot  water  to  plumbing  fixtures  is  usually  a  difficult 
detail  to  arrange.  This  subject  is  discussed  under  Class  Dio, 
"Branches  to  Hot-Water  Plumbing  Fixtures,"  and  in  Class  A3i, 
"  Steam  for  Heating  Purposes." 

Class  H14  —  Low-Pressure  Water;  to  Separate  Buildings.  If 
the  location  of  the  power  plant  under  consideration  is  such  that 
it  is  advisable  to  furnish  warm  water  to  car  shops,  offices  or 
similar  nearby  buildings,  it  will  be  found  quite  objectionable 
to  take  this  supply  from  the  feed  mains  since  they  should  be  left 
for  boiler  feeding  with  the  least  possible  number  of  unnecessary 
connections.  If  a  comparatively  large  quantity  of  water  is 
required  for  outside  feeding  another  supply  should  be  arranged, 
designed  for  low  pressure.  If  there  is  an  abundance  of  exhaust 
steam  the  simplest  way  would  be  to  take  low-pressure  cold  water 
from  the  regular  low-pressure  system  and  allow  it  to  pass  through 
a  small  exhaust  heater  used  especially  for  this  purpose.  If  the 
exhaust  steam  is  less  than  that 
condensed  by  the  boiler  feed- 
water  heater  then  this  indepen- 
dent heater  should  be  placed 
ahead  of  the  feedwater  heater, 
thus  first  raising  the  tempera- 
ture of  the  water  in  it  to  about  *gy/*?y?[j  7  u  j 
210  degrees,  even  though  the 
feedwater  heater  may  not  raise 

the  temperature  of  its  water  ~FIG  238  (Hl4-i). 

above  150  degrees  or  less.  If 
all  the  exhaust  steam  is  condensed  in  heating  the  feedwater  then 
the  live  steam  heater  shown  in  Fig.  132  (A3 2-2)  is  quite  as 
economical  as  an  exhaust  heater. 

If  it  is  necessary  to  pipe  both  live  steam  and  low-pressure  cold 
water  for  a  considerable  distance  to  the  outside  buildings  where 
hot  water  is  also  required,  and  if  the  steam  is  always  turned  on 
and  the  exhaust  is  condensed  for  feedwater,  then  the  use  of  a 
live  steam  water-heater  would  be  the  more  economical  method 
of  furnishing  hot  water.  Thus  less  water  would  be  wasted  by 
running  off  the  cold  water  in  the  pipes  when  it  is  desired  to  get 
the  warm  water.  The  live  steam  heater  has  another  advantage 


288  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

in  that  the  temperature  can  be  regulated  and  that  all  the  conden- 
sation may  be  delivered  to  the  water-heater  by  taking  steam 
from  the  bottom  of  a  drip  pocket.  This  practice  will  save  drips 
which  otherwise  might  be  wasted  to  the  sewer. 

If  the  plant  is  operated  with  the  engines  exhausting  to  atmos- 
phere then  all  these  small  savings  gained  by  using  a  live  steam 
heater  are  of  no  consequence  because  such  heat  secured  from 
the  exhaust  is  obtained  without  any  expenditure  for  fuel. 

If  it  is  necessary  to  place  the  steam  water-heater  in  an  out- 
lying building  it  may  be  found  advisable  to  lay  out  the  hot-water 
piping  on  the  loop  system.  This  will  keep  the  water  in  circula- 
tion so  that  it  will  be  warm  throughout  all  the  piping.  Fig.  238 
(Hi4~i)  shows  such  an  arrangement  of  piping  from  which  hot 
water  may  be  instantly  drawn  without  drawing  off  the  water  in 
the  main. 


CHAPTER    XVIII. 
CONDENSER    COOLING    WATER    PIPING. 

Class  II  —  Condenser  Cooling  Water;    Intake  from  Waterway. 

The  economy  secured  by  the  use  of  condensing  machinery  is 
such  as  to  warrant  considerable  outlay  in  providing  a  sufficient 
supply  of  water  and  the  apparatus  necessary  for  condensing  pur- 
poses. Ordinarily  a  condenser  equipment  will  save  from  6  to 
8  Ib.  of  steam  per  hp.-hr.  At  this  rate  for  a  i,ooo-hp.  unit  the 
saving  would  be  about  10  tons  of  coal  per  day  which,  at  $1.50  per 
ton,  would  amount  to  $5,475  per  year.  If  the  engine  were  run 
only  half  of  the  total  time  the  saving  would  be  more  than  $2,500 
per  year  which,  at  12  per  cent  for  interest  and  depreciation, 
would  justify  an  expenditure  of  $20,000  for  condensing  appa- 
ratus In  most  cases,  however,  the  condensing  apparatus  would 
not  cost  more  than  the  amount  that  it  would  save  in  fuel  if  it 
operated  one-half  of  each  day  for  a  year's  time.  In  other  words, 
a  loo-hp.  condensing  unit  operating  under  the  conditions  as 
stated  would  save  about  $2,000  per  year  after  the  proper  amount 
for  interest  and  depreciation  had  been  deducted. 

If  the  supply  of  water  for  condensing  purposes  is  reliable  the 
initial  cost  of  condensing  apparatus  may  be  considered  from  an 
entirely  different  standpoint.  The  total  cost  of  buildings, 
boilers,  piping,  engines,  etc.,  necessary  to  develop  one  horse- 
power may  approximate  $50;  then  the  cost  of  condensing 
apparatus,  including  waterways,  apparatus,  etc.,  would  be  some- 
what less  than  $4  per  horsepower  capacity  of  the  total  plant,  or 
about  $12  for  each  horsepower  furnished  by  the  condenser.  It 
will  be  noted  that  the  cost  per  horsepower  for  any  installation  is 
less  for  a  condensing  plant  than  for  a  non-condensing  one,  which 
will  permit  the  use  of  less  boiler  and  engine  horsepower  if  the 
plant  is  built  for  condensing.  It  is  safe  to  state  that  if  water  is 
obtainable  for  condensing  from  any  other  source  than  city  water- 
works the  saving  in  installation  and  operation  will  justify  the 
expenditure  necessary  for  condensing  apparatus. 

289 


290 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


In  Fig.  239  (Ii-i)  a  power  plant  with  high  and  low  level  of 
water  supply  is  shown  in  cross-section.  In  studying  the  water- 
supply  problem  for  such  a  plant  the  following  points  should  be 
be  considered:  The  distance,  a,  should  be  as  short  as  possible 
and  not  over  16  ft.;  this  is  on  account  of  pump  suction  and 
expense  for  deep  waterway.  The  distance,  b,  should  be  not  less 
than  3  ft.,  which  will  allow  the  suction  pipe  to  be  2  ft.  in  the 
water  when  it  is  at  the  low  level.  By  making  b  about  3  ft.  it 


FIG.  239  (Ii-i). 

would  be  possible  to  operate  the  plant,  even  though  for  any  rea- 
son the  water  should  drop  a  foot  or  so  lower  than  the  previous 
low-water  level.  The  distance,  c,  is  the  extreme  variation 
between  high  and  low-water  levels.  The  distance,  d,  should  be 
as  much  more  than  c  as  possible  so  as  to  give  ample  fall  for 
sewers.  If  it  is  necessary  to  make  this  but  12  in.  more  than  c, 
then  there  should  be  a  sewer  valve,  e,  that  can  be  used  in  case  of 
higher  water  level  than  that  established.  The  distance  to  the 
top  of  the  hot- well,  /,  should  be  sufficiently  greater  than  c,  to  pre- 
vent any  unusually  high  water  level  (more  than  c)  from  causing 
an  overflow  of  water  into  the  building. 

A  knowledge  of  the  geography  of  the  power  plant  locality 
is  quite  necessary  when  making  plans  for  obtaining  condensing 
water.  The  chief  requirement  in  such  a  situation  is  "  to  get  wg  ier." 
The  amount  required  may  vary,  but  a  sufficient  volume  must 
always  be  available  for  condensing.  Possibly  no  other  feature 
of  station  engineering  requires  so  much  investigation,  study  and 
preparation  as  this  one  problem.  Evidently  there  is  no  ideal 
condition  of  condenser  water-supply.  The  nearest  approach 


CONDENSER   COOLING   WATER   PIPING. 


291 


to  the  ideal  is  when  the  plant  stands  close  to  a  deep,  wide  stream 
having  but  slight  variation  in  its  level.  But  such  supplies  are  not 
generally  to  be  had  where  plants  are  needed. 

On  the  other  hand,  the  station  may  be  located  close  to  a  small 
stream  that  flows  between  narrow  banks,  overflowing  one  season 
and  almost  dry  another.  This  is  a  typical  situation  for  condenser 
water-supply  and  to  overcome  its  most  serious  objections  it  will 
generally  be  found  necessary  to  build  a  dam,  thus  allowing  the 
water  to  accumulate  in  a  pond  from  which  the  power  plant  supply 
may  be  drawn.  This  body  of  water  may  then  be  used  as  a 
cooling  pond  if  the  water  supply  should  become  less  than  that 
circulated  by  the  condenser  pumps.  Under  such  conditions  the 
amount  of  water  necessary  to  replenish  that  lost  by  evaporation 
would  be  little  or  no  more  than  that  required  for  boiler  feeding. 

In  Fig.  240  (1 1-2)  is  shown  a  pond  built  in  the  basin  of  a 
stream  which  formerly  flowed  between  the  limits  shown  by  the 
dotted  lines.  The  banks  for  such  a  pond  should  be  raised  to  a 


height  such  that  the  waste  water  at  overflow  times  will  be  confined 
to  its  proper  channel  and  not  cut  through  the  banks,  but  pass 
over  a  waste  waterway  dug  through  firm  soil  and  having  sufficient 
high  ground  between  it  and  the  basin  to  prevent  erosion.  A 
small  overflow  should  be  laid  in  firm  soil  and  located  slightly  below 
the  overflow  into  the  waste  waterway,  thus  permitting  the  circula- 
tion of  water  in  and  out  of  the  basin  if  there  is  but  a  small  surplus. 
Should  there  be  a  considerable  surplus  of  water  then  the  con- 
denser can  be  discharged  away  from  the  pond  through  the  line,  A, 


292  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

and  the  main  supply  be  kept  much  cooler.  The  line,  B,  located 
lower  than  the  bottom  of  the  pond,  provides  for  complete  drainage. 

In  the  design  and  construction  of  work  of  this  character  no 
water  pipe  should  be  laid  in  a  dam  or  fill.  For  instance,  it  may 
appear  desirable  to  run  a  metal  drain  from  the  bottom  of  the 
pond  to  the  down-side  of  the  steam,  laying  this  pipe  in  the  same 
place  and  at  the  same  time  as  the  dam  is  made.  The  difficulty 
that  would  arise  in  such  a  case  would  not  be  caused  by  the  pipe 
carrying  water  through  it,  as  a  long  piece  of  timber  would  make 
the  same  trouble.  That  is,  the  water  from  the  pond  would  form 
a  slight  leakage  along  the  surface  of  the  pipe  or  timber  extending 
through  the  earth  work,  and  once  a  channel  had  been  cut  through 
it  would  only  be  a  short  time  before  the  hole  would  become  enlarged 
and  the  fill  endangered. 

The  earth  fill  should  not  be  subjected  to  having  water  pass  over 
or  through  it,  but  it  should  be  carried  to  a  sufficiently  high 
elevation  to  force  the  waste  water  to  flow  over  firm  undisturbed 
soil  and  between  banks  of  like  character.  This  can  best  be  accom- 
plished by  leveling  a  large  tract  of  ground  so  that  the  waste  water 
will  flow  over  it  and  into  the  down-stream  side.  This  spillway 
should  be  a  sufficient  distance  from  the  pond  to  preclude  any 
possibility  of  washing  away  the  bank  dividing  them  and  protecting 
the  dam.  Precautions  must  be  taken  to  prevent  water  flowing 
over  or  through  any  made  ground  or  its  destruction  will  occur. 

It  will  be  noted  in  Fig.  240  that  the  small  overflow  from  the 
pond  is  carried  through  virgin  soil.  The  one  difficulty  met  in 
building  such  a  line  is  due  to  the  fact  that  the  pipe  is  placed  in  a 
trench  which  must  be  refilled  with  made  ground.  This  difficulty 
can  be  overcome  by  making  the  length  of  the  overflow  line  suffi- 
cient to  prevent  water  finding  its  way  through.  As  the  overflow 
has  practically  no  head  of  water  above  the  fill  which  surrounds  the 
pipe,  the  water  has  a  very  slight  tendency  to  leak  along  the  surface. 
The  same  precautions  should  be  observed  with  the  condenser 
discharge  trench  and  the  trench  for  the  line,  .4,  if  the  latter  is  laid 
at  a  high  level,  say  12  in.  below  the  small  pond  overflow.  How- 
ever, if  these  lines  are  at  a  low  elevation,  say  6  or  8  ft.  below  the 
surface  of  the  pond,  it  will  then  be  necessary  to  make  the  trench 
of  considerable  length  from  the  pond  to  the  point  of  discharge; 
and  to  further  insure  the  tightness  of  the  trench  and  its  ability  to 
prevent  any  appreciable  water  flow  it  will  be  necessary  to  puddle 


CONDENSER  COOLING   WATER  PIPING.  293 

the  fill,  using  plenty  of  water  to  settle  the  replaced  dirt.  If  clay 
is  obtainable  for  refilling  the  trenches,  then  a  short  trench  may  be 
made  tight  if  care  is  taken  in  placing  the  pipe.  In  fact,  it  will  be 
found  possible  to  make  a  trench  when  carefully  refilled  with  clay, 
even  more  secure  from  leakage  than  the  surrounding  ground,  if 
the  latter  be  of  a  sandy  nature. 

Too  much  importance  cannot  be  placed  upon  the  necessity  of 
carefully  making  the  fill  below  the  pipe,  because  it  is  at  this  point 
that  seepage  and  trouble  occur.     Referring  to  Fig.  241  (1 1-3)  the 
space,  a,  would  naturally  be  filled  loosely  unless  special  care  were 
taken.     It  makes  no  difference  how  far  the  earth 
is  dropped  when  being  replaced,  it  will  still  pack 
only  at  the  sides,  b,  and  the  more  firmly  it  is 
packed  here  the  less  able  is  the  dirt  to  move 
sideways  and  closely  fill  under  the  pipe.     The 
weight  of  the  fill  has  no  tendency  to  force  the 
filling  under  the  pipe  and  there  is  no  pressure 
on  the 'earth,  c,  directly  under  the  pipe,  unless 
it  is  caused  by  deliberate  filling,  wetting  and     FIG.  241  (11-3). 
ramming.  ^  As   this    is    a    part    of    the   trench 
where  a  channel  can  be  cut  without  the  sides  closing  in,  it  is 
invariably  at  this  point  that  leakages  occur  through  pipe  trenches 
as  such  leakage  will  continue  cutting  away  the  earth  until  a  suf- 
ficient amount  of  earth  has  been  removed  to  allow  the  pipe  to 
settle  into  the  opening  and  cause  trouble  from  leakage  or  possibly 
breakage. 

Whenever  there  is  a  head  of  water  on  a  trench  too  much  im- 
portance cannot  be  placed  upon  the  details  of  filling.  For  such 
work  it  is  necessary  to  use  metal  pipe  with  perefectly  tight  joints. 

Fig.  242  (1 1-4)  shows  a  water  supply  which  is  higher  than 
the  ground  surrounding  the  building.  It  would  seem  that  such  a 
condition  would,  in  itself,  suggest  that  the  pipe  line  must  be  water- 
tight throughout  its  entire  length. 

Where  tile  or  other  leaky  pipes  are  used  the  manner  of  filling  a 
trench  does  not  enter  into  the  seepage  problem.  There  is  nothing 
gained  in  keeping  a  trench  tight  if  the  pipe  passing  through  it  has 
openings  permitting  seepage.  It  is  important  to  lay  tile  pipe  so 
that  it  is  well  supported.  This  precaution  should  be  taken  if  for 
no  other  reason  than  to  prevent  open  joints  that  sand  may  wash 
into.  Where  the  water  pressure  outside  the  pipe  is  equal  to  that 


294 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


inside,  tile  pipe  will  be  found  quite  as  suitable  as  metal  and  will 
cost  much  less  and  last  longer. 

For  a  situation  such  as  shown  in  Fig.  242  some  form  of  a  built- 
in-the-trench  reinforced-concrete  water  conduit  would  be  found 
suitable  as  the  pressure  inside  would  be  slight  and  but  little  rein- 
forcing be  required.  Such  a  conduit  should  be  built  by  one 


FIG.  242  (Ii-4). 

familiar  with  the  methods  necessary  for  insuring  watertight  work, 
the  chief  requisite  for  such  work  being  continuous  progress  after 
the  concrete  placing  has  been  started,  thus  avoiding  joining  the 
fresh  work  with  that  which  has  set. 


FIG.  243  (Ii-s). 

Another  method  of  constructing  the  line  shown  in  Fig.  242, 
though  subject  somewhat  to  interruption  through  breakdown, 
would  be  to  use  a  large  cistern  at  the  power  house  and  a  float  which 
would  electrically  operate  the  admission  valve,  thus  maintaining 
at  all  times  a  constant  level  in  the  cistern.  This  would  avoid  the 
rise  of  water  to  the  surface  of  the  ground  and  at  the  same  time 
permit  the  use  of  tile  pipe.  The  regulation  can  be  accomplished 
by  using  a  synchronous  moter  for  operating  the  admission  valve 


CONDENSER  COOLING   WATER  PIPING.  295 

and  a  small  alternating-current  generator  driven  by  a  motor  at  the 
cistern.  The  current  supply  to  the  motor  may  be  controlled  by 
the  float  as  shown  in  Fig.  243  (1 1-5). 

Under  such  conditions  the  pond-float  operates  the  pair  of  con- 
tacts as  shown  supported  at  a.  These  contact  points  engage  with 
other  contacts  when  a  change  of  water  level  occurs  and  complete 
a  circuit  through  a  direct-current  motor  operating  it  in  either  one 
direction  or  the  other.  The  motor  driving  the  generator  shown 
also  operates  the  screw,  c.  This  withdraws  the  contact  points 
which  the  float  has  caused  to  engage.  The  pivot  a  may  so  be 
located  to  obtain  any  desired  travel  of  the  contacts  and  thus  keep 
the  variation  of  water  level  within  the  specified  limits.  The 
arrangement  as  shown  in  Fig.  243  (1 1-5)  is  set  for  a  variation 
of  4  ft.  in  the  cistern  level  and  would  have  the  inlet  valve  entirely 
open  at  low  level,  half  way  open  at  midpoint  and  entirely  closed  at 
the  high-water  mark.  The  position  of  the  valve  at  any  point  is 
proportional  to  the  water  level  in  the  cistern.  This  system  of 
control  is  a  modification  of  the  electric  damper  regulator  as  used 
in  power  houses,  except  that  with  the  damper  regulator,  instead 
of  the  motor  driving  the  generator,  it  operates  a  cable  connected 
to  the  damper.  The  contacts  in  the  damper  system  are  operated 
by  the  gage  of  the  regulator. 

This  method  of  regulation  by  the  use  of  motors  can  be  used  for 
open  waterways  or  for  cisterns  having  a  great  difference  in  elevation 
and  where  the  pipes  connecting  the  source  of  supply  with  the  cistern 
cannot  be  filled  entirely  with  water.  The  control  would  be  much 
more  sensitive  if  the  supply  pipe  throughout  its  entire  length  were 
below  the  water  level  of  the  pond.  Then  the  amount  of  water 
entering  the  basin  would  exactly  equal  that  admitted  by  the  valve. 
If  the  demand  for  water  suddenly  be  cut  off,  that  within  the  pipe 
would  not  be  emptied  into  the  basin  as  would  be  the  case  if  the  pipe 
were  not  below  the  level  of  the  pond. 

A  considerable  reserve  capacity  must  be  provided  if  the  pipe 
discharges  above  the  water  level  of  the  cistern  because  it  must  then 
be  of  sufficient  size  to  receive  the  contents  of  the  pipe  that  would 
flow  to  it  after  the  admission  valve  were  closed. 

So  many  varying  conditions  are  met  in  different  localities  that 
it  is  impossible  to  say  which  is  the  most  suitable  material  to  use  for 
the  construction  of  large  waterways.  Much  depends  upon  the  soil 
through  which  the  line  must  be  run.  If  the  line  is  of  considerable 


296 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


length,  —  say  100  ft.  or  more,  or  of  such  size  that  a  suction  16  in. 
or  more  in  diameter  is  required,  then  the  water  should  be  delivered 
by  gravity.  In  many  cases  the  soil  close  to  the  water's  edge  is 
unfit  for  supporting  building  foundations.  This  often  necessitates 
the  placing  of  a  power-house  some  distance  from  the  water.  The 
fact  that  the  soil  is  unsuitable  for  building  purposes  makes  it  quite 
as  unsuitable  for  building  a  trench  and  placing  a  waterway  through 
it.  If  the  plant  is  located  alongside  of  a  dock  much  difficulty  may 
be  experienced  with  old  piles,  dock  timbers,  etc.,  and  since  it  is 
desirable  to  carry  the  pipe  line  under  water  the  entire  distance 

such  conditions  would  hinder  careful 
construction  and  necessitate  installing 
a  pump  of  sufficiently  large  capacity 
to  care  for  the  increased  amount  of 
seepage  through  loose  ground. 

Fig.  244  (1 1-6)  shows  an  intake 
constructed  of  sheet  piling.  The  lower 
line  of  plank  is  driven  inside  of  the 
upper  row.  Sheet  piling  is  necessary  in 
soft  soil,  both  to  hold  back  the  sides 
and  to  confine  the  water  to  the  desired 
course.  The  material  between  the 
walls  of  the  trench  can  be  removed  while 
the  planks  are  being  driven.  Struts  and 
stringers  as  shown  take  the  thrust  of  the 
banks.  After  the  material  has  been  re- 
moved between  the  walls  of  the  trench 

the  lower  stringers,  a,  are  placed  and  the  bottom  secured  to  them. 
Before  removing  the  upper  row  of  sheet  piling  and  filling  in  the 
trench  the  plate,  b,  should  be  set  approximately  correct  when 
driving  the  piling  and  planked  over  as  at  c. 

If  placed  entirely  below  the  water  level,  a  waterway  constructed 
in  this  manner  will  last  indefinitely  so  long  as  the  wood  is  protected 
from  the  atmosphere  at  all  times.  The  planking  can  be  made 
double  and  the  waterway  made  secure  against  the  pressure  of  the 
banks  and  material  be  prevented  from  washing  through  the  joints 
of  the  plank.  To  properly  carry  the  tile  pipe  it  would  be  advis- 
able to  use  this  form  of  construction  as  far  back  from  the  water  as 
the  made  ground  extends,  or  at  least  until  firm  ground  is  reached. 
Tile  pipe  may  be  used  inside  of  the  sheet  piling  as  far  as  the  water's 


FIG.  244  (Ii-6). 


CONDENSER   COOLING   WATER   PIPING. 


297 


edge,  but  where  it  is  necessary  to  build  up  a  complete  enclosure  of 
wood  to  hold  back  the  banks  and  seepage  water,  there  is  nothing  to 
be  gained  by  placing  another  conduit  inside  of  the  wooden  one. 

If  the  intake  line  is  entirely  below  the  water,  as  would  be  the 
case  in  Fig.  244,  or  as  in  the  case  of  a  pipe  line,  there  should  be 
wells  placed  at  regular  intervals,  about  150  ft.  apart  along  the 
line  of  the  intake,  to  facilitate  the  removal '  of  sand  or  other 
deposits  which  may  collect  in  the  pipe.  Since  they  are  exposed 
to  varying  conditions  of  moisture,  these  wells  should  be  of 
masonry.  The  bottom  of  the  wells  should  be  at  least  3  ft.  below 
the  bottom  of  the  pipe.  This  will  permit  the  deposit  to  collect 
in  the  wells  along  the  line,  thus  acting  as  small  catch-basins. 
Metal  steps  should  be  built  in  the  sides  of  the  wells  and  the  tops 
should  be  fitted  with  iron  manhole  rings  and  covers. 

There  have  been  intake  lines  built  of  o.25-in.  steel  or  iron  plate 
with  flanges  at  the  end  for  bolting  the  sections  together.  The 
most  serious  objection  to  this  type  of  construction  is  its  short 
life  and  the  fact  that  the  sections  are  built  in  lengths  of  about 
1 6  ft.  —  which  are  difficult  to  handle  in  the  trenches.  Such  long 
sections  necessitate  extreme  care  in  maintaining  a  perfectly 
straight  line  of  trench  and  a  special  arrangement  of  struts,  etc., 
must  be  provided  to  permit  the  lowering  of  the  pipe. 

If  the  waterway  is  of  large  dimensions  and  conditions  permit, 
it  should  be  constructed  of  concrete;  this  is  the  best  material 
which  can  be  used  and  it  is 
probably  the  cheapest.  The 
shape  and  method  of  construct- 
ing a  concrete  pipe  will  be 
governed  by  the  condition  of 
the  soil  through  which  it  is 
run.  If  the  waterway  is  cut 
through  shale  or  rock,  vertical 
sides  and  a  flat  bottom  will  be 
found  the  most  economical 
form  to  construct.  Such  a 
conduit  is  shown  in  Fig.  245 
(1 1-7).  There  is  no  object  FIG.  245  (Ii-y). 

in    using    rounded    sides    or 

bottom  where  the  banks  are  fully  able  to  support  the  weight 
on  them  without  exerting  a  lateral  strain  on  the  walls.  If 


298  STEAM  POWER   PLANT  PIPING  SYSTEMS, 

the  banks  at  the  points,  a-a,  are  secure  and  will  permit  the 
concrete  being  rammed  hard,  the  top  may  be  constructed  as 
an  arch.  But  if  the  banks  are  weak,  there  is  no  object  in 
making  the  top  arched,  as  it  would  not  have  a  solid  skew- 
back  to  resist  the  thrust.  In  this  case  it  would  be  safer  and 
require  less  material  to  build  a  flat  top  and  use  metal  rods  at 
the  lower  portion  of  the  top,  thus  reinforcing  the  concrete.  If 
the  banks  are  of  loose  sand,  similar  to  quicksand,  then  an  egg- 
shaped  conduit  should  be  used:  in  clay,  it  would  be  possible  to 
build  the  waterway  of  hard  brick  and  require  very  little  forming, 
the  bottom  being  used  as  a  form  to  lay  the  brick. 

In  whatever  form  the  waterway  is  constructed  it  should  be 
so  graded  in  regard  to  low  water  and  have  such  a  height  that  a 
man  could  walk  through  it  when  the  water  is  low.  For  instance, 
if  the  bottom  of  the  waterway  is  3  ft.  below  low  water  it  should 
not  be  less  than  5  ft.  high  in  the  clear,  allowing  2  ft.  above  the 
water  for  a  man  to  breathe  while  cleaning  the  bottom.  The  wells 
which  run  down  to  the  intake  should  not  be  over  150  ft.  apart,  as 
the  air  in  the  waterway  would  become  stifling  if  the  distance 
between  the  manholes  is  greater  than  this.  The  waterway,  as 
stated,  may  collect  sand,  etc.,  and  when  the  water  is  high  and 
the  conduit  is  full  of  water  a  man  could  not  get  in  to  clean -it  out. 
This  would  not  cause  trouble,  as  there  would  be  plenty  of  water 
available  even  though  there  were  2  or  3  ft.  of  sand  on  the'bottom. 
The  trouble  would  arise  only  at  times  when  the  water  level  would 
be  low,  in  which  case,  however,  it  could  be  easily  remedied. 

Instead  of  using  forms  in  the  trench  for  building  the  concrete 
walls  they  can  be  built  on  the  surface  of  the  ground,  in  a  wooden 
mold,  using  light  wire  mesh  for  reinforcement,  This  will  per- 
mit the  use  of  very  light  concrete  walls,  possibly  6  in.  for  a 
3  by  5-ft.  conduit,  which  could  be  assembled  as  shown  in  Fig. 
246  (1 1-8).  Two  patterns  only  are  required  for  the  molds, 
and  all  the  concrete  blocks  can  be  made  and  be  ready  for  use 
when  the  trench  is  opened.  By  this  method  of  construction 
the  trench  would  be  open  only  a  short  time  and  many  of  the 
difficulties  occurring  from  caving  in  would  be  avoided. 
Another  advantage  of  this  form  of  conduit  would  be  that  the 
blocks  could  be  laid  in  water  without  injuring  the  concrete.  The 
loops  shown  at  a  should  be  of  heavy  wire  or  rods  built  into  the 
block  to  facilitate  handling  them  with  a  crane.  Tongue  and 


CONDENSER  COOLING   WATER  PIPING. 


299 


grooved  joints  should  be  used  in  this  construction.  The  lifting 
eyes,  a,  in  the  bottom  slabs  may  be  cut  off  after  they  are  in  place 
or  recessed  below  the  surface.  With  this  construction  only  a 
small  amount  of  labor  would  be  required  for  assembling,  as  the 
sections  could  be  formed  by  common  laborers.  The  sections 
should  be  put  together  with  cement  in  the  joints  and  made  as 
tight  as  tile  pipe,  which  would  be  quite  sufficient  for  this  class  of 


FIG.  246  (I i -8). 


FIG.  247  (Ii-9). 


work.  The  weight  of  these  sections  —  4  ft.  by  4  ft.  by  6  in., 
taken  at  140  Ib.  per  cu.  ft.  —  would  be  1,120  lb.,  which  could 
easily  be  handled  by  a  crane. 

Whatever  the  construction  of  the  intake  may  be,  it  is  necessary 
to  guard  the  mouth  so  as  to  prevent  the  entrance  of  leaves,  sticks, 
fish,  ice,  logs,  etc.  If  the  water  supply  is  liable  to  freeze  around 
the  intake  to  such  an  extent  that  the  supply  might  be  endangered, 
a  line  with  a  regulating  valve  in  it  should  be  run  from  the  con- 
denser discharge  so  that  warm  water  can  be  delivered  at  the 
intake  and  freezing  thus  be  prevented.  The  intakes  should  be 
fitted  with  screens  of  different  mesh,  arranged  so  that  they  can 
easily  be  removed  for  cleaning. 

The  accompanying  figures  show  a  screen  house  designed  by 
the  writer.  Fig.  247  (1 1-9)  is  the  plan  view  showing  the 
double-screen  compartment  with  a  3-ft.  opening  into  and  out  of 
each  compartment.  All  four  of  these  openings  are  arranged  for 


300 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


FIG.  248  (Ii-io). 


FIG.  249  (Ii-u). 


CONDENSER   COOLING    WATER   PIPING. 


301 


the  valve  shown  in  Fig.  250  (1 1-12)  which  permits  shutting 
off  either  of  the  screen  compartments  without  interfering  with 
the  operation  of  the  plant.  There  are  two  valves  for  this  screen- 
house.  By  placing  them  on  the  outside  of  the  opening  as  shown 
in  elevation,  Fig.  249  (Ii-n),  it  is  possible  to  shut  off  all  the 
openings.  The  section  shown  in  Fig.  248  (Ii-io)  shows  one 
of  these  valves  in  place.  The  valves,  when  not  in  use,  are  under 


FIG.  250  (Ii-i2_). 

cover,  and  by  keeping  them  well  painted  they  are  always  in  con- 
dition ready  for  use.  The  lower  end  of  the  long  lever  has  a 
wrought-iron  piece  which  forms  a  pivot  upon  a  heavy  "  scrub- 
brush  handle"  cast  on  the  iron  casing-ring.  The  upper  end  and 
also  the  lower  portion,  just  above  the  valve,  are  each  provided 
with  an  eye  to  facilitate  raising  the  valve  out  of  the  water;  the 
end  of  the  trolley-beam  is  extended  outside  of  the  building  for 
this  purpose. 

The  valve  shown  is  made  of  wood  of  double  thickness  with  well 
leaded  joints  and  a  soft  sponge-rubber  ring  i  in.  square  in  section 
fitted  around  the  space  at  the  edge  to  make  a  water-tight  joint. 
The  screw-rod  which  extends  through  the  wall  and  handle-nut  are 
provided  to  draw  the  lever  up  tight  against  the  valve  and  force  the 
valve  against  its  seat.  The  adjusting  screw  is  located  inside  of 
the  building  so  that  it  is  out  of  reach  of  meddlers.  The  flagging 
shown  in  Figs.  247  and  249  permits  a  man  to  get  out  of  the  front 
of  the  screen -house  and  for  attaching  a  small  chain  hoist  to  the 
end  of  the  trolley-beam.  An  8-in.  I-beam  is  used;  not  that  the 


302  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

weight  it  is  required  to  carry  is  so  great,  but  in  order  to  provide 
room  for  trolley  wheels  of  ample  size. 

The  screen  guides  are  made  of  cast  iron  with  lugs  to  key  them 
into  the  concrete.  The  screen  frames  are  made  of  angle  irons  of 
heavy  section.  Such  screens  should  be  made  of  copper  wire,  not 
of  brass,  as  brass  wire  will  not  stand  the  sharp  bends  necessary  in 
screens  of  fine  mesh.  A  much  cheaper  screen  can  be  made  of  iron 
wire,  but  the  life  of  such  screens  is  so  short  that  there  is  no  economy 
in  their  use. 

It  will  be  seen  from  the  illustration  that  there  is  a  large  settling 
chamber  between  the  screen  compartment  and  the  mouth  of  the 
intake  to  permit  sand,  etc.,  to  settle.  It  will  also  be  noted  that  the 
height  of  the  waterway  is  such  that  at  low  water  there  is  a  space  of 
3  ft.  between  the  surface  of  the  water  and  the  top  of  the  intake. 
The  floor  space  over  the  settling  chamber  is  necessary  for  the 
cleaning  of  screens.  Sufficient  room  has  been  left  between  the 
tiers  of  screens  to  permit  dropping  a  brush  or  rake  between  them 
to  remove  leaves,  etc.,  without  removing  the  screen.  The  warm 
water  discharge  from  the  condenser  is  not  shown  in  these  illustra- 
tions. It  consists  of  a  line  of  i2-in.  pipe  extended  to  the  intake 
and  carried  alongside  of  the  intake  waterway  and  outside  of  the 
screen-house,  discharging  through  the  bank  retaining  wall  at  about 
low- water  level. 

Spread  footings  were  not  required  for  this  screen-house,  as  the 
foundation  rested  on  rock.  Had  the  bottom  been  of  sand,  the 
bottom  of  the  intake  foundation  would  have  been  concrete  of  a 
considerably  greater  thickness  and  possibly  reinforced  with  iron 
bars.  In  case  of  fine  sand,  which  is  liable  to  wash,  the  footing 
should  be  protected  and  anchored  to  avoid  shifting  in  case  of 
freshets  or  floating  ice.  Fig.  251  (11-13)  shows  the  projected 
footing  loaded  with  heavy  stone  carefully  piled  around  the  screen- 
house.  The  footings  should  be  projected  in  front  as  well  as  at  the 
sides  and  placed  sufficiently  low  that  they  can  be  loaded  with  stone. 
By  finishing  the  banks  and  bottom  of  the  intake  in  this  manner 
much  less  difficulty  will  be  experienced  from  sand,  etc.,  being 
washed  in. 

If  it  is  necessary  to  build  the  intake  house  near  an  old  dock, 
filled-in  banks  or  similar  location  where  a  firm  bottom  for  founda- 
tions cannot  be  secured,  it  may  be  found  advisable  to  use  piles  and 
build  the  top  of  the  piles  into  the  concrete  as  shown  in  Fig.  252 


CONDENSER   COOLING   WATER   PIPING. 


303 


(Ii-i4).     The  concrete  bottom  should  be  put  in  at  the  same  time 

as  the  walls  and  the  concrete  around  the  piles,  thus  giving  a  footing 

over  the  entire  surface  as  well  as  on  the  piles.     To  further  increase 

the  stability  of  this  structure,  the  spread  footings  shown  in  Fig.  251 

may  be  used,  but  this  necessitates  more  complicated  forms  for  the 

concrete.     The  forms  for  Fig.  252  can  be  placed  in  the  water  after 

the  ground  has  been  removed  around  the 

piles    and    the    concrete    built    up    without 

pumping  the  water  out.     The  outside  forms 

rest  on  the  bottom  and  the  inside  forms  are 

supported    on    the    piles.      Better   concrete 

work   can    be    made    in   this  way  than  by 

pumping   the   water  from   the   center,  thus 

causing     it    to    wash     through    the    fresh 

concrete. 


m 


m 


FIG.  251  .(11-13). 


jl 

FIG.  252  (11-14) 


In  constructing  intake  waterways  there  should  be  no  passage 
between  the  water  supply  and  the  screen  chamber  which  is  not 
easily  accessible.  This  detail,  however,  is  frequently  neglected 
and  in  nearly  every  case  without  good  reason.  A  water  conduit 
from  the  center  of  the  stream  to  the  screen-box  is  shown  by  the  full 
lines  in  Fig.  253  (11-15).  The  waterway  shown  at  A  is  very 
objectionable  as  it  is  sure  to  clog  and  cause  trouble.  If  there  is  not 
a  rapid  flow  at  the  intake,  then  it  is  advisable  to  place  the  screen 
compartment  and  intake  either  at  the  point  shown  dotted  in  the 
center  of  the  waterway  with  a  runway  leading  to  it  or  at  the  screen- 
box,  and  cut  away  the  banks  so  that  the  water  will  flow  directly 
into  the  screen  compartment  as  shown  in  the  illustration.  If  the 
source  of  supply  is  a  stream  which  carries  leaves  and  floating  debris, 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


the  screen-house  or  box  should  not  be  set  into  the  banks  of  the 
stream  unless  some  provision  is  made  to  carry  off  the  floating 
material.  The  most  desirable  location  for  the  screen-house  is  to 
place  it  so  that  the  front  face  is  on  the  same  line  as  the  stream  and 
not  recessed  in  the  bank,  as  ice  and  logs  will  then  accumulate  in 
the  entrance  space.  Neither  should  the  screen-house  project  into 
the  stream  unless  it  is  well  protected,  as  it  is  liable  to  be  injured  in 
times  of  flood  by  floating  ice  and  logs. 

Where  cooling  ponds  are  used  for  reducing  the  temperature  of 
the  condensing  water,  a  screen-house  such  as  that  shown  dotted  in 
Fig.  253  (11-15)  would  be  suitable,  as  it  would  take  water  from 


FIG.  253  (11-15). 

the  center  of  the  pond  where  it  is  deepest  and  coolest.  Little 
difficulty  would  be  experienced  from  leaves,  etc.  Many  installa- 
tions such  as  this  are  operated  without  an  intake  crib  or  screen,  the 
opening  into  the  crib  being  located  well  below  the  surface  of  the 
water. 

There  are  many  suburban  power  stations  being  operated  non- 
condensing  that  could  be  very  readily  operated  with  a  cooling  pond 
and  condenser.  Cooling  ponds  can  ordinarily  be  constructed  for 
about  one  dollar  per  boiler  horsepower,  not  including  waterways, 
etc.  This  would  make  the  cost  of  a  i,ooo-hp.  engine  plant  using 
15  Ib.  of  steam  per  engine  horsepower,  about  $500,  or  50  cents  per 
engine  horsepower  in  excess  of  that  where  a  natural  water  supply 
is  available. 

Cooling  towers  are  frequently  used  for  this  service,  but  these 
cost  at  least  $3.00  per  engine  horsepower,  including  the  founda- 
tions, fan-drive,  etc.  Not  only  are  they  more  expensive  to  install, 
but  are  much  more  expensive  to  operate,  owing  to  the  fact  that 
the  circulating  water  must  be  elevated  to  the  top  of  the  tower. 
This  is  usually  about  30  ft.,  and  the  entire  head  is  lost  in  dripping 


CONDENSER   COOLING   WATER  PIPING.  30$ 

over  the  cooling  surfaces.  To  this  loss  must  be  added  the  power 
required  for  driving  the  blast  fans  in  those  types  which  do  not 
have  a  natural  circulation  of  air.  Cooling  towers  generally  have 
less  than  one  square  foot  of  cooling  surface  per  pound  of  steam, 
the  average  cooling  surface  being  0.7  sq.  ft.  per  pound  of  steam. 
Cooling  ponds  should  be  as  large  as  conditions  will  permit;  not  that 
smaller  ponds  would  not  be  sufficient  to  maintain  the  desired 
vacuum,  but  because  of  the  quantity  of  water  which  must  be  cir- 
culated if  the  temperature  is  high.  As  an  increase  in  the  amount 
of  circulating  water  increases  the  amount  of  power  lost,  the  money 
thus  wasted  would  more  than  equal  the  interest  on  the  investment 
for  a  pond  of  larger  dimensions. 

The  fact  that  a  plant  is  at  a  considerable  elevation  above  the 
water  supply,  whether  it  is  stream  or  cooling  pond,  does  not  prevent 
installing  a  condenser  plant  successfully.  An  elevated  jet-con- 
denser is  admirably  suited  for  such  a  layout  as  shown  in  Fig.  254 
(Ii-i6).  This  is,  in  many  respects,  a  more  plausible  arrange- 
ment than  to  run  the  exhaust  up  to  the  condenser  bowl 
located  at  a  higher  elevation.  The  safest  arrangement  is  to  have 
the  exhaust  drain  into  the  condenser  as  shown  in  Fig.  254 
(Ii-i6),  but  the  conditions  are  generally  such  that  it  cannot  be  so 
arranged. 

The  most  serious  difficulty  to  be  overcome  in  such  installations 
is  the  construction  of  the  intake,  discharge  and  condenser  well. 
This  will,  however,  depend  upon  the  condition  of  the  soil  and  can 
probably  be  accomplished  by  placing  the  waterway  in  trenches 
until  the  depth  becomes  excessive  and  then  tunnel  the  remainder 
of  the  distance  to  the  well.  The  circulating  pump  and  heater 
pump  would  be  located  entirely  under  water  and  would  therefore 
not  require  stuffing  boxes  where  the  shaft  passes  through  the  case. 
In  fact,  the  suction  may  be  taken  in  the  center  through  both  the 
top  and  the  bottom  of  the  impeller  case.  The  only  parts  requiring 
attention  would  be  the  shaft  journals,  and  as  the  shaft  exerts  such 
a  slight  pressure  on  the  bearings  and  would  generally  be  lubri- 
cated with  grease,  the  care  required  would  be  insignificant.  The 
motors  would  be  placed  above  the  engine-room  floor,  free  from 
heat,  vapor,  etc.,  where  they  could  readily  be  looked  after  by  the 
operator. 

In  case  the  water  supply  is  below  a  high  steep  bluff,  the  con- 
denser shaft  could  be  cut  in  the  face  of  the  bluff  and  the  screen- 


306 


STEAM  POWER  PLANT  PIPING  SYSTEMS, 


FIG.  255  (Ii-iy) 


CONDENSER   COOLING    WATER   PIPING.  307 

house  built  in  the  cut  as  shown  in  Fig.  255  (Ii-iy).  A  rather 
long  exhaust  main  would  then  be  necessary,  the  only  objection, 
however,  being  the  increased  cost  of  the  line.  The  fact  that  the 
exhaust  main  would  be  exposed  to  the  atmosphere  would  be  an 
advantage,  as  it  then  would  aid  in  condensing  the  steam.  The 
expansion  and  contraction  could  easily  be  cared  for  by  allowing 
the  condenser  bowl  to  move  freely  with  the  pipe,  the  tail-pipe  being 
sufficiently  long,  so  that  considerable  travel,  possibly  a  foot  or  more, 
could  be  taken  care  of.  The  water  to  the  heater  would,  in  this  case, 
require  being  well  insulated  to  prevent  freezing.  The  condenser 
building  and  screen-house,  etc.,  should  be  built  of  concrete  through- 
out. A  reinforced  concrete  roof  and  a  metal  stairway  from  the 
ground  down  to  the  screen  and  motor-floor  level  should  be  installed. 
The  motors  in  this  installation  should  each  have  a  switch  at  the 
switchboard,  and  each  motor  should  have  a  separate  wattmeter  or 
an  ammeter  so  that  any  variations  or  unusual  conditions  could 
be  detected  from  the  power  station. 

At  least  once  during  each  watch  the  engineer  on  duty  should 
make  a  careful  inspection  of  the  motors,  condenser,  etc.  This 
duty  would  in  no  way  be  a  hardship  upon  the  operator,  and  with 
this  amount  of  attention  no  trouble  should  arise  because  of  the 
motors  being  out  of  his  sight.  There  are  many  motors  in  daily 
use  which  may  be  only  a  few  feet  from  the  operator,  but  are  so 
situated  that  they  are  entirely  out  of  view  for  possibly  a  day  or 
more  at  a  time. 

The  wires  from  the  station  to  the  condenser  tower  should  be 
carried  in  some  form  of  insulated  underground  conduit,  thereby 
avoiding  any  possibility  of  trouble  from  lightning.  It  will  be 
noted  that  the  power  house  shown  in  Fig.  255  may  be  located  at  a 
considerable  height  above  the  condenser  allowing  the  exhaust  pipe 
to  run  down-hill  to  the  condenser.  This  distance  may  be  100  ft. 
or  more,  in  which  case  this  is  about  the  only  simple  and  practical 
method  of  installing  a  condenser  where  the  water  lies  so  far  below 
the  power  plant. 

Another  method,  one  which  would  be  more  complex,  is  to 
locate  the  jet  condenser  or  surface  condenser  in  the  power  house 
in  the  usual  manner  and  raise  the  water  to  the  condenser.  The 
fall  of  the  water  from  the  power  house  to  the  level  of  the  source 
of  supply  may  be  utilized  by  means  of  a  Pelton  waterwheel  or 
other  similar  device.  The  waterwheel,  electric  motor  and  a  turbine 


308  STEAM   POWER   PLANT  PIPING   SYSTEMS. 

pump  for  raising  the  injection  water  being  all  mounted  on  the 
same  shaft,  the  motor  would  only  have  to  supply  the  power 
necessary  to  overcome  the  friction  in  the  pipes,  loss  of  head  in  the 
condenser  and  the  loss  due  to  the  inefficiency  of  the  pump  and 
water  motor.  Instead  of  running  the  exhaust  and  heater  supply 
pipes  from  the  power  station  to  the  condenser  house,  it  would  then 
be  necessary  to  run  the  circulating  water  line  from  the  source  to 
the  power  house. 

Whichever  plan  of  supplying  the  water  to  the  condenser  is 
employed,  the  water  used  for  condensing  should  not  be  raised  to 
a  high  elevation  and  the  available  head  thus  created  be  allowed  to 
waste.  For  instance,  a  surface  condenser  may  be  placed,  say, 
32  ft.  above  the  surface  of  the  water  supply,  and  if  all  the  joints 
are  water  tight  no  loss  will  be  occasioned  by  raising  the  water  to 
this  elevation  and  allowing  the  discharge  to  fall  from  this  height, 
provided  that  the  entire  section  of  the  pipe  from  the  pump  back 
to  the  discharge  is  air-tight.  The  power  required  to  raise  water 
above  32  ft.  would  be  lost  or  wasted  in  this  case,  as  the  limit  of 
height  of  a  water  column  that  the  atmosphere  will  support  is  32  ft. 
To  utilize  any  additional  head,  a  device  such  as  a  Pelton  wheel  or 
turbine  waterwheel  would  be  necessary,  as  previously  described. 

The  most  efficient  method  of  supplying  circulating  water 
would  be  to  run  the  exhaust  down  to  the  condenser  rather  than  to 
raise  water  more  than  32  ft.  to  a  surface  condenser,  or  any  amount 
whatever  to  a  jet  condenser.  The  most  economical  location  for 
a  jet  condenser  of  the  elevated  type  is  with  the  overflow  aa  little 
as  possible  above  the  surface  of  the  water  supply  as  it  will  enable 
the  condenser  to  discharge  its  water.  This  condition  is  ordinarily 
obtained  by  locating  the  overflow  from  the  condenser  at  extreme 
high- water  level,  allowing  the  water  in  the  hot- well  to  raise  a  foot 
or  so  during  short  intervals. 

Class  12  —  Condenser  Cooling  Water;  Discharge  from  Condenser. 
The  elevation  of  the  discharge  waterway  from  an  elevated  jet 
condenser  should  be  determined  by  the  location  of  the  hot-well 
overflow,  but  for  surface  condensers  the  water  should  be  discharged 
at  the  same  elevation  as  it  is  taken,  whether  the  water  supply  is 
at  high  or  low  water.  A  surface  condenser  can  and  should  be 
operated  without  perceptible  loss  of  head  in  the  circulating  water, 
other  than  that  caused  by  the  friction  of  the  water  in  the  pipe, 
condenser  tubes,  etc. 


CONDENSER   COOLING    WATER   PIPING. 


309 


l 


An  elevated  jet  condenser  necessitates  two  losses  of  head :  First, 
that  due  to  the  difference  in  weight  between  the  solid  cold  water 
in  the  injection  column  and  that  flowing  through  the  condenser 
and  tail  pipes.  The  other  loss  is  due  to  the  fact  that  the  condenser 
would  be  located  in  relation  to  extreme  high  water,  and  would 
ordinarily  be  operated  at  a  lower  level,  necessitating  a  loss  of  power 
due  to  the  quantity  of  water  used  and  raised  from  the  level  of  the 
water  supply  to  the  level  of  the  overflow.  These  combined  losses 
of  head  will  be  about  10  ft.  in  case  the  water  is  being  pumped 
from  4  ft.  below  the  high-water  level. 

A  surface  condenser  would  not  have  these  losses,  but  a  loss 
of  head  is  occasioned  which  does  not  exist  in  the  jet  condenser. 
This  loss  of  head  is  occasioned  by  the  circuitous  and  restricted 
path  of  the  cooling  water  through  the  small  condenser  tubes. 
The  loss  may  be  more  or  less  than  that  of  the  jet  condenser, 
depending  upon  the  cleanliness  of  the 
condenser  tubes,  but  this  alone  is  too 
slight  an  advantage  to  be  a  deciding 
factor  in  selecting  the  type  of  condenser 
to  be  used. 

The  jet  type  is  the  most  commonly 
used  condenser  with  suction  instead  of 
pressure  pumps  such  as  are  employed 
with  the  elevated  types.  There  are, 
however,  many  objectionable  features 
in  the  suction  jet  condenser  that 
cannot  be  eliminated  unless  the  con- 
densing chamber  is  elevated.  Fig. 
256  (l2-i)  shows  a  jet  condenser  of 
this  type  arranged  to  secure  the  great- 
est efficiency  possible  and  at  the  same 
time  to  be  fairly  reliable.  The  unfor- 
tunate feature  of  this  arrangement 
is  that  efficiency  must  be  sacrificed  to 
insure  uninterrupted  operation.  To 
secure  the  greatest  possible  efficiency 
with  this  device,  it  is  necessary  to  make  the  distance,  A,  such 
that  a  column  of  water  of  that  height  would  be  the  equivalent 
of  the  column  of  mercury  whose  height  is  equal  to  the  vacuum 
which  it  is  intended  to  maintain.  This  would  necessitate 


1 


FIG.  256  (l2-i). 


310  STEAM  POWER  PLAXT  PIPING  SYSTEMS. 

A  being  28  ft.  for  a  25-in.  vacuum.  It  would  also  be  neces- 
sary for  the  discharge  to  be  carried  down  into  the  discharge 
waterway,  the  water  in  which  is  as  nearly  as  possible  at  the  same 
elevation  as  the  intake  or  supply  water.  If  this  type  of  condenser 
could  be  operated  and  constructed  in  this  manner  it  would  be 
working  under  exactly  similar  conditions,  and  have  the  same 
efficiency  as  a  condenser  of  the  elevated  type. 

The  atmospheric  pressure  in  the  type  shown  in  Fig.  256  (21-1) 
would  support  the  water-leg  A,  and  the  pump  would  simply  have 
to  overcome  the  difference  in  weight  of  the  two  columns.  The 
elevated -jet  type  of  condenser  has  its  discharge  leg  (tail-pipe) 
of  length  A,  and  as  this  is  a  longer  column  than  the  vacuum  will 
support,  a  pump  is  used  to  counterbalance  the  difference  between 
the  injection  and  discharge  legs.  To  secure  the  same  economy 
for  the  condenser  shown  in  Fig.  256  as  could  be  obtained  with  the 
elevated- jet  type,  it  is  necessary  to  instill  it  in  the  manner  stated. 
This,  however,  is  impracticable  for  two  distinct  reasons:  One 
because  the  pump  would  not  be  able  to  lift  water  28  ft.,  and  the  other 
because  the  moment  the  vacuum  drops  below  25  in.  the  water 
would  fail  to  flow  into  the  condenser  and  the  entire  vacuum 
would  be  lost.  One  is  a  difficulty  met  in  starting  the  condenser, 
the  other  in  regular  operation.  The  less  the  distance  A ,  the  more 
certain  is  the  operation.  Many  condensers  of  this  type  are  in 
operation  with  the  lift,  A,  as  great  as  16  ft.  and  with  a  vacuum 
as  low  as  14  in. 

In  order  to  start  a  condenser  with  such  a  high  lift  it  is  necessary 
to  use  a  "  false  injection,"  that  is,  a  water  supply  delivered  to  the 
injection^ pipe  under  pressure  as  shown  at  b,  in  Fig.  256.  In  this 
case  a  foot-valve  must  be  provided  at  the  lower  end  of  the  injection 
pipe  and  a  gage  attached  at  the  top  of  the  line  to  show  when  the 
vacuum  has  raised  the  water  into  the  condenser  from  the  intake. 
The  false  injection  is  used  only  until  a  sufficient  vacuum  has  been 
formed  in  the  condenser  bowl  to  raise  the  water  from  the  intake. 
Another  method  of  supplying  a  false  injection  is  through  a  separate 
line  and  sprayer  fitted  in  the  bowl  as  shown  by  dotted  lines  at  c. 
This  avoids  the  necessity  of  a  foot-valve  and  the  attendant  losses 
by  friction  in  the  flow  of  the  water. 

This  type  of  condenser,  it  will  be  noted,  has  a  much  lower 
efficiency  than  the  elevated  type.  Even  if  the  lift  A  is  made  as 
great  as  16  ft.  there  is  a  loss  of  head  of  12  ft.  over  that  of  the 


CONDENSER   COOLING   WATER  PIPING.  3,!  I 

elevated  type,  making  a  total  of  about  18  ft.  including  the  loss 
through  the  condenser  bowl.  This  loss  would  be  but  6  ft.  in  the 
elevated  condenser,  or,  in  other  words,  only  one-third  the  power 
would  be  required  for  handling  the  circulating  water,  assuming 
the  pumps  to  be  of  the  same  type  and  make.  If  the  discharge 
connection  from  the  condenser  is  in  any  way  open  to  the  atmosphere 
at  the  upper  end  as  at  d,  in  Fig.  256,  then  the  loss  of  head  will  be 
still  greater,  possibly  the  full  28  ft.  In  this  case  the  power  required 
would  be  four  and  a  half  times  that  of  the  elevated  type.  The 
discharge  from  the  pumps  should  be  kept  perfectly  air-tight,  as 
this  line  is  carrying  air  and  water  from  the  pump  the  same  as  the 
tail-pipe  on  the  elevated  type.  If  it  were  possible  to  discharge  the 
water  at  a  much  lower  elevation  than  the  intake,  then  the  pump 
could  be  entirely  dispensed  with  and  the  water  would  flow 
through  the  condenser  and  maintain  the  vacuum,  becoming  in 
operation  a  device  similar  to  the  elevated  condenser. 

The  discharge  would  in  this  case  have  to  be  at  least  34  ft.  long, 
and  the  distance  from  the  surface  of  the  intake  to  the  surface  of  the 
discharge  water  must  not  be  less  than  24  ft.  This  also  is  true  of  the 
elevated-jet  condenser,  except  that  the  latter  will  operate  with  a 
smaller  difference  between  the  water  levels,  as  far  as  starting  up 
is  concerned,  but  would  require  the  same  difference  in  the  water 
levels  as  the  suction  type  if  operated  without  the  pump  when  the 
vacuum  has  dropped  to  14  in. 

Another  important  advantage  in  the  use  of  the  elevated  type 
of  condenser  over  the  suction  jet  condenser  is  in  the  style  of 
pumping  machinery  which  can  be  used.  In  the  case  of  the 
suction  jet  condenser  the  pump  must  handle  a  much  larger 
volume  per  horsepower,  as  it  not  only  has  to  pump  the  water, 
but  the  air  which  was  contained  in  it  as  well.  As  this  air  has 
expanded  from  atmospheric  pressure  to  the  pressure  in  the  con- 
denser, the  total  volume  to  be  handled  by  the  pump  is  about 
eight  times  the  volume  of  the  injection  water  alone.  Further, 
the  class  of  work  which  the  suction  pump  must  do  is  very  severe, 
both  on  the  pump  and  the  valves,  owing  to  the  shock  which  is 
caused  when  water  and  air  are  handled  together  in  one  pump. 
As  the  pump  for  the  elevated  condenser  handles  only  water  and 
that  at  a  low  pressure,  the  centrifugal  pump  is  admirably  suited 
for  this  class  of  service.  It  can  be  operated  very  economically 
either  from  a  pulley  on  a  jack  shaft  or  direct-connected  to  an 


312  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

electric  motor.  The  power  required  for  the  water-ends  of  the 
two  types  of  pump  is  nearly  the  same  when  the  same  work  must 
be  done  by  each. 

The  steam  required  to  drive  a  steam  pump  is  generally  many 
times  that  required  by  centrifugal  pumps  if  driven  by  the  main 
engines.  The  steam  pump  would  require  more  than  100  Ib.  of 
steam  per  hp.-hr.  while  the  main  generating  unit  would  prob- 
ably use  less  than  20  Ib.  per  hp.-hr.  Hence,  the  steam  required 
for  operating  centrifugal  pumps  would  be  from  one-fifth  to  one- 
fourth  that  required  by  the  steam  pump. 

If  there  is  an  insufficient  supply  of  auxiliary  exhaust  steam 
for  heating  the  feed  water  it  would  be  more  economical  to  run 
the  condenser  pump  by  steam.  The  reason  for  this  is  evident,  as 
a  pound  of  steam  for  the  main  engine  would  contain  1,100  B.t.u., 
while  the  pound  of  steam  used  in  the  pump  would  require  but  50 
B.t.u.  This  will  be  the  difference  between  the  heat  in  a  pound 
of  steam  at  boiler  pressure  and  a  pound  at  atmospheric  pressure, 
as  the  remainder  of  the  heat  is  returned  to  the  boiler  in  the 
feed  water. 

In  determining  the  form  of  drive  to  be  employed  for  auxiliary 
machinery,  the  ability  of  the  plant  to  utilize  the  exhaust  steam 
must  be  considered.  In  the  ideal  steam  plant  the  highest 
economy  is  obtained  when  the  exhaust  from  the  steam  driven 
auxiliaries  is  just  equal  to  the  steam  that  the  feed  water -will  con- 
dense. The  efficiency  of  these  machines  is  then  as  great  as  pos- 
sible, for  all  the  heat  which  is  not  converted  into  work  is  returned 
to  the  boiler. 

The  hot-well  is  necessary  for  the  successful  operation  of  the 
elevated-jet  condenser,  as  it  provides  a  seal  to  keep  the  tail-pipe 
filled  and  prevent  the  access  of  air  to  it,  which  otherwise  would 
reduce  the  vacuum  obtainable.  In  Fig.  220  there  was  shown  a 
satisfactory  method  of  taking  feed  water  without  disturbing  the 
water  in  the  hot- well.  Fig.  221  showed  a  pump  box  such  as  would 
be  used  with  a  suction  pump  jet  condenser  or  a  surface  con- 
denser. With  such  apparatus  there  is  no  necessity  for  a  hot-well 
or  water  seal.  A  pump  box  would  not  be  required  for  a  surface 
condenser,  as  the  feed  could  be  taken  from  the  condenser  cham- 
ber as  shown  in  Figs.  226  and  228.  The  most  satisfactory 
arrangement  for  the  pump  box  shown  in  Fig.  221  is  to  place  it 
in  the  discharge  waterway  at  the  lower  end  of  the  discharge  for 


CONDENSER   COOLING    WATER   PIPING. 


313 


such  installations  as  shown  in  Fig  256,  and  allow  the  feed  pump 
to  raise  the  water  out  of  its  compartment.  As  previously  stated 
theie  should  be  no  opening  to  the  atmosphere  at  the  upper  end  of 
the  discharge,  shown  at  d,  in  Fig.  256  (l2-i),  to  accommodate 
a  pump  box  above  the  floor. 

It  is  true  that  the  feed  pump  must  raise  the  water  higher  when 
the  pump  box  is  placed  at  the  discharge  waterway,  but  it  should 
be  remembered  that  the  feed  water  is  only  about  3  per  cent  of  the 
condenser  water,  and  it  is  therefore  more  economical  to  raise 
3  per  cent  the  additional  height  rather  than  to  raise  the  97  per 
cent. 

As  shown  in  Fig.  257  (1 2-2),  the  bottom  of  the  discharge 
waterway  should  be  slightly  lower  at  the  point  where  the  thaw- 


FIG.  257  (12-2). 

ing-out  pipe  is  run  into  the  intake.  The  mouth  of  the  discharge 
should  be  slightly  higher  than  the  intersection  marked  "low- 
point"  to  insure  water  flowing  through  the  line  at  times  of  low 
water.  The  discharge  of  the  thawing  pipe  should  be  a  suffi- 
cient distance  below  the  water  to  protect  it  against  freezing. 
The  entire  thawing  line  should  have  not  less  than  five  feet  of 
earth  over  it.  In  case  the  water  is  taken  from  the  cooling  pond 
it  would  be  unnecessary  to  provide  a  thawing  line  to  the  mouth 
of  the  intake. 

The  mouth  of  the  discharge  into  the  cooling  pond  should  be 
provided  with  an  oil  or  grease  catcher  to  prevent  grease  from 


314  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

getting  into  the  pond.  This  is  necessary  not  only  to  prevent  the 
disfigurement  of  the  banks  and  surface  of  the  pond,  but  also 
to  prevent  the  liability  of  oil  reaching  the  boilers.  A  simple 
grease  catcher  is  shown  in  Fig.  258  (12-3).  This  may  be  con- 
structed of  wood,  concrete,  brick,  or  other  desirable  material. 
The  discharge  from  this  compartment  is  through  an  opening 
located  as  far  as  possible  below  the  surface  of  the  water.  The 


FIG.  258  (12-3). 

opening  from  the  grease-catching  compartment  is  provided  with 
a  valve  and  handle  for  operating  it.  Inside  of  the  grease-collect- 
ing compartment  is  an  overflow  into  a  trough  which  discharges 
into  a  sewer  or  grease-catching  cistern.  The  grease  i^  allowed  to 
accumulate  in  this  compartment  until  the  operator  desires  to 
draw  it  off,  the  latter  process  being  accomplished  by  opening 
the  trap  to  observe  the  overflow,  and  by  closing  the  valve  suf- 
ficiently to  cause  the  water  level  in  the  compartment  to  rise  to  the 
skimmer  edge  and  overflow  into  the  sewer.  An  objection  to  this 
skimming  device  is  that  the  sewer  will  become  clogged  with  the 
gum  and  grease  discharged  into  it.  To  avoid  this  difficulty  and 
at  the  same  time  save  the  grease  it  would  be  profitable  to  place 
the  grease  tank  between  the  overflow  and  the  sewer,  as  shown  in 
Fig.  259  (12-4).  It  may  seem  at  first  thought  that  the  arrange- 
ments proposed  are  rather  elaborate  for  the  purpose  of  remov- 
ing grease,  but  if  some  such  provision  is  not  made  the  condition 
of  the  pond  at  the  end  of  five  years  or  so  would  be  unbearable. 
It  should  be  remembered  that  all  the  cylinder  oil  leaving  the 
engine  remains  in  the  pond,  and  it  is  very  probable  that  30  or 


CONDENSER  COOLING   WATER  PIPING. 


31$ 


40  barrels  of  cylinder  oil  would  be  scattered  along  the  banks, 
intake,  etc.,  in  this  period  of  time. 

In  reference  to  the  elevated  jet  condenser  discharge,  a  modifica- 
tion of  that  shown  in  Figs.  253  and  254  can  be  made  by  placing 
the  condenser  bowl  at  the  power  house  and  instead  of  running  the 


FIG.  259  (l2-4). 

tail-pipe  vertically  it  can  be  run  down  the  bank  in  a  covered  trench, 
allowing  ample  means  for  expansion  and  contraction  as  shown  in 
Fig.  260  (12-5).  The  hot-well  in  this  case  would  be  made  con- 
siderably larger.  The  volume  of  the  hot-well  measured  from 
the  discharge  opening  in  the  tail-pipe  to  the  water  level  must  be 
greater  than  the  contents  of  the  entire  tail-pipe  up  to  the  condenser 


FIG.  260  (12-5). 

bowl.  With  this  arrangement  it  would  be  necessary  to  run  three 
pipes  in  the  trench  —  the  injection  line,  tail-pipe  and  heater  supply. 
To  provide  for  the  low-pressure  water  service  in  the  plant  it 
would  be  advisable  to  have  two  small  low-pressure  pumps  in 
addition  to  the  motor-driven  circulating  pump.  It  would  further 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


be  advisable  to  have  two  centrifugal  pumps  attached  to  the  motor 
shaft,  one  of  which  should  take  water  from  the  hot-well  and  the 
other  from  the  intake.  This  arrangement  would  require  four  pipe 
lines  from  the  screen-house  to  the  basement.  This  condenser 
system  is  suitable  only  where  the  proper  elevations  can  be  secured, 
the  distance  from  the  base  of  the  condenser  to  the  water  level  being 
approximately  34  ft.  .In  determining  the  details 
of  the  intake  and  discharge  waterway  and  the 
location  of  the  condensers,  pumps,  etc.,  the  water 
requirements  should  also  be  duly  considered. 
These  requirements  are  for  boiler 
feed,  general  cold  water  service 
and  fire  protection. 

If  the  power  house  is  to  furnish 
fire  protection  for  other  buildings 
as  well,  it  would  be  necessary  to 
provide    steam    pumps    for    this 
service,   if    for    no    other 
reason  than  to  comply  with 
the    requirements    of    the 
board  of  fire  underwriters. 
It  will  be   observed    that 
the  plants  shown  in  Figs. 


FIG.  261  (12-6). 

253,  254  and  260  fail  to  provide  suitable  equipment  for  this 
service.  It  also  will  be  noted  that  these  different  services 
require  electrically-driven  pumps  as  shown,  leaving  only  the 
exhaust  from  the  feed  pumps  for  heating  the  feed-water,  and 
a  loss  of  economy  follows  as  previously  stated  under  this  class 
heading,  "1-2."  To  make  possible  the  use  of  steam-driven 
pumps  it  would  be  necessary  to  locate  the  floor  of  the  pump  room 
so  low  that  the  pump  could  lift  the  water.  This  can  be  accom- 
plished as  shown  in  Fig.  261  (1 2-6). 


CONDENSER   COOLING   WATER   PIPING. 

The  following  pumps  should  be  placed  in  the  pump  room:  The 
condenser  circulating  water  and  underwriter's  fire  pumps,  hot-well 
pump  to  the  heater  and  low-pressure  pump  from  the  intake.  The 
air  pump,  if  employed,  may  be  located  in  the  room  directly  over 
the  pump  room. 

To  overcome  the  difficulty  of  opening  up  a  trench  as  deep  as 
shown  for  the  waterway  it  may  be  found  more  economical  to  use 
scrapers  and  lower  the  section  of  ground  between  the  condenser  and 
screen-house  so  that  the  ground  over  the  waterway  lies  just  below 
the  pump-room  floor  as  shown  by  the  grade  lines,  a.  This  would 
make  a  trench  about  16  ft.  deep  for  the  intake  instead  of  possibly 
30  to  35  ft.  deep.  By  lowering  the  ground  in  this  manner  there 
could  be  a  door  from  the  pump  room  and  a  walk  leading  down  to 
the  screen-house,  and  this  would  also  provide  more  room  for  win- 
dows in  the  pump  room,  which  is  very  desirable.  If  a  surface 
condenser  is  employed  practically  the  same  arrangement  would  be 
adopted  for  a  circulating  pump  and  fire  pump  in  the  pump  room, 
but  the  condenser  and  wet-vacuum  pump  would  be  located  as  close 
to  the  engines  as  possible.  The  pump  room  and  the  well  to  the 
waterway  can  be  made  considerably  smaller,  in  fact  the  waterways 
may  be  run  directly  under  the  pump  and  be  fitted  with  a  manhole 
opening  and  ladder  leading  down  to  the  water.  The  floor  of  the 
pump  room  shown  in  Fig.  261  may  also  be  run  over  the  intake  and 
hot-well,  there  being  no  serious  objection  to  this  arrangement,  as 
there  is  no  machinery  located  in  the  well,  as  would  be  the  case  in 
Figs.  253  and  254.  Fig.  261  unquestionably  is  the  most  practical 
system  for  plants  located  at  a  considerable  distance  above  the 
water  supply,  as  it  is  possible  to  start  the  pump  and  obtain  the  full 
vacuum  before  the  engines  are  started,  and  thus  avoid  interruption 
caused  by  the  opening  of  circuit-breakers  and  the  stopping  of  the 
pump  motors. 

The  system  is  more  economical  from  an  operating  standpoint, 
and  it  would  be  in  most  cases  as  economical  to  construct  as  any 
of  the  other  systems  described,  due  to  the  fact  that  only  standard 
apparatus  is  employed.  It  would  be  necessary  in  such  a  system 
to  have  an  elevated  water  tank  and  priming  lines  connected  to  all 
the  pumps  in  the  pump  room  so  that  they  can  be  started  with  a  14 
or  i6-ft.  suction. 

Class  13,  4  and  5  —  Condenser  Cooling  Water ;  Main  and  Branches 
to  Pumps  and  Condensers.  If  the  plant  is  fitted  with  more  than 


3l8  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

one  condenser  or  more  than  one  pump,  a  main  should  be  provided 
into  which  all  the  pumps  discharge  and  one  from  which  all  the  con- 
densers receive  their  water.  This  arrangement  enables  the  opera- 
tion of  any  of  the  pumps  with  any  of  the  different  condensers. 
Such  an  arrangement  is  particularly  essential  in  the  case  of  motor- 
driven  pumps,  as  it  permits  the  use  of  as  many  pumps  as  may  be 
required.  The  pressure  on  these  lines  would  be  very  slight,  in 
fact  they  may  be  under  vacuum,  this  being  determined  by  the  style 
of  the  condensers  and  the  relative  elevations  of  the  line  with  respect 
to  the  condensers.  Light  cast-iron  pipe  is  very  suitable  for  this 


FIG.  262  (13-1). 

service,  but  special  provision  must  be  made  for  the  expansion  and 
contraction  with  changes  of  temperature.  Valves  should  be 
placed  in  each  branch  and  should  also  be  located  along  the  main 
so  that  each  condenser  unit  may  be  isolated,  together  with  its 
pumps,  as  shown  in  Fig.  262  (13-1). 

By  arranging  lines  in  this  manner,  it  is  possible  to  shut  down 
any  portion  of  the  main  to  make  repairs  and  permit  the  remaining 
portion  to  operate  without  interruption.  The  size  of  the  main 
required  is  only  that  required  for  one  condenser  or  two  pumps, 
and  for  three  condensers  would  simply  be  the  size  of  the  branch 
pipe  to  the  condenser.  This  main  is  also  desirable  if  the  pumps 
are  steam  driven,  as  it  makes  the  injection  water  more  easy  to 
control.  A  pressure  gage  should  be  placed  on  the  main  to  indicate 
whether  the  pumps  are  delivering  more  water  than  required,  which 
would  cause  the  pressure  to  increase,  or  whether  the  supply  is 
insufficient,  which  would  result  in  a  decrease.  The  injection 
valves  (or  admission  valves  to  a  surface  condenser)  are  generally 
controlled  by  hand,  and  as  they  are  opened  or  closed  to  meet  the 
demand  of  the  condensers,  the  capacity  of  the  pumps  is  also 
changed,  due  to  the  increased  or  decreased  pressure  against  which 
they  are  delivering.  It  is  therefore  quite  impossible  to  keep  the 
quantity  of  cooling  water  properly  regulated,  as  the  conditions 


CONDENSER   COOLING   WATER  PIPING. 


.319 


constantly  change,  so  that  if  the  water  supply  is  adjusted  at  a 
sufficiently  large  amount  to  insure  the  maximum  vacuum  obtain- 
able, then  the  tail  water  is  for  the  greater  portion  of  the  time  at  a 
yery  low  temperature.  If  the  quantity  of  water  is  reduced  to  raise 
the  temperature  of  the  discharge  water,  then  the  vacuum  will  be 
less  than  that  which  is  obtainable,  except  when  the  load  may  be 
temporarily  light. 

The   ideal    method    of   controlling   the   circulating   of   cooling 
water  would  be  by  means  of  a  thermostatic  regulator  operated 
by  the  temperature  of  the  tail  water,  opening  or  closing  the  inlet 
valve  as  quickly  and  as  often   as  the  temperature  of  the  dis- 
charge changes.     Controlling   the   quantity  of  injection   by  the 
vacuum  is  very  uncertain  and  undesirable,  as  it  is  evident  that 
if  leaks  should  occur  or  for  any  other  reason, 
such   as   the  condenser  becoming    air-bound, 
and  the  vacuum  drop,  the  quantity  of  injec- 
tion would  be  abnormally  increased,  resulting 
in  too  low  a  temperature  of  the  tail  water  and 
a  waste  of  power  in  the  circulating  pump,  as 
the  extra  supply  of   injection    is    useless.     A 
thermostatic     regulator     for     controlling    the 
quantity  of  the   injection   water  is  shown   in 
Fig.   263    (13-2).     The   regulator,   as   will   be 
seen,   consists  of  an  expansion  tube  which  is 
permanently  attached  to  a  point  near  the  lower 
end  of  the  tail-pipe  and  attached  to  the  injec- 
tion valve  by  an  adjusting  screw  which  per- 
mits the  regulator  to  be  adjusted.     The  length 
of  the  tube  is  so  chosen  that  it  will  give  the 
desired  travel  to  the  valve.     As  copper  has  a 
higher  coefficient  of  expansion  than  cast-iron, 
as    the    temperature    of    the    injection    water 
becomes    too    high,    the    lengthening    of    the 
copper  tube  increases  the  opening  through  the  injection   valve, 
which   admits   more  water  and  constantly  lowers  the  tempera- 
ture of  the  injection.     Should  the  temperature  of  the  tail  water 
become  too  low,   it  is  evident  that  the  reverse   process  occurs. 
The  shaft,  sprocket,  etc.,  shown  by  dotted  lines  on  the  diagram, 
are  for  a  valve  extension  so  that  the  valve  can  be  operated  from 
the  floor  if  desired.     A  thermometer  placed  in  the  tail-pipe  and 


FIG.  263  (13-2). 


320.  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

a  vacuum  gage  connected  to  the  exhaust  pipe  should  be  placed  near 
the  operating  handle  of  the  injection  valve  so  that  the  attend- 
ant may  observe  the  vacuum  and  temperature  of  the  discharge 
when  adjusting  the  amount  of  injection  water  supplied  to  the 
condenser. 

In  reading  the  vacuum  gage  a  correction  must  be  made  to 
allow  for  the  column  of  water  in  the  pipe  if  there  is  a  long  drop 
or  rise  in  the  gage  connection.  Each  foot  of  pipe  filled  with 
condensation  is  equal  to  about  an  inch  on  the  vacuum  gage. 
It  is  seldom  that  two  or  more  vacuum  gages  will  read  the  same, 
due  to  the  difference  in  the  length  of  their  water  columns.  The 
pointer  on  a  gauge  is  set  to  show  the  pressure  at  the  gage  connec- 
tion, and  if  the  pipe  runs  from  either  above  or  below  the  gage 
and  water  collects  in  the  pipe,  the  gage  will  read  incorrectly. 
To  determine  the  extent  of  this  inaccuracy,  the  gage  should  be 
read  and  the  line  then  quickly  blown  out  and  the  gage  re-read, 
at  the  same  time  noting  the  pressure  on  some  other  gage  to  ascer- 
tain whether  the  pressure  remained  constant  while  the  gage  con- 
nection was  being  blown  out. 

Class  16,  7  and  8  —  Condenser  Cooling  Water;  Connections 
for  Other  Service  than  Condensing.  In  regular  operation,  the 
feed  pump  would  draw  water  directly  from  the  hot-well  or  from 
the  hot-well  pump  which  would  deliver  the  warm  water  to  an 
open  heater,  from  which  the  feed  pump  would  deliver  it  to  the 
boiler.  The  fire  pump  would  draw  its  water  from  the  intake 
line  only,  regardless  of  whether  it  is  supplying  low-pressure  main 
or  the  high-pressure  lines  in  a  case  of  a  fire.  The  pump  that  is 
used  for  tube-drilling  should  have  an  intake  connection,  and  the 
feed  pump  should  also  have  a  connection  to  the  intake  for  use 
when  the  condenser  is  not  in  operation.  To  facilitate  the 
arrangement  of  these  different  connections  with  the  circulating 
water  lines  it  is  generally  found  that  the  best  arrangement  is  to 
run  both  the  intake  and  discharge  waterways  under  the  build- 
ing in  such  a  way  that  all  the  pumps  can  take  their  suction  directly 
from  the  waterways  without  the  necessity  of  using  a  long  suction 
main  to  which  the  different  pumps  are  attached,  with  their  numer- 
ous pipe  joints,  valves,  etc. 

When  laying  out  waterways  for  condensing  machinery  it  should 
be  remembered  that  there  are  other  uses  for  the  water  which  if 
not  properly  provided  for  at  the  start  will  lead  into  complicated 


CONDENSER  COOLING   WATER  PIPING. 


321 


FIG.  264  (I6-i). 


and  troublesome  pump  suctions.     If  the  intake  is  laid  out  as  a  part 

of  the  building  construction  and  the  portion  under  the  building  is 

completed  before  making  a  connection  to  the  water  supply,  there 

should  be  no  particularly  difficult  features  met  in  its  construction. 

The  location  of  the  waterways  that  is  best  adapted  for  all  the 

various  connections   is   parallel   with   the  dividing  wall  between 

the   engine   and   the   boiler   room,    the  various 

pumping  machinery  being  set  along  the  wall  and 

over  or  just  to  one  side  of  the  waterway.     To 

avoid     the     possibility    of    loosening    the    soil 

alongside  of  the  waterway  and  provide  a  safe 

footing    for   the   division  wall,   crane   columns, 

etc.,  it  would  be  found  both  a  safer  and  more 

economical  construction  to  support  the  walls  on 

the  masonry    of    the    waterway    as    shown    in 

Fig.  264   (I6-i).     The  top  and  bottom  of  the 

waterway  may  be  reinforced  as  shown.     Sleeves 

should  be  placed  in  the  concrete  for  the  suction 

pipe  to  pass  through,  and  manholes  provided 

with  ladders  built  into  the  concrete  should  be 

placed  in   the  waterway  to  facilitate  entrance  for  cleaning   or 

inspection. 

In  nearly  every  case  the  condenser  discharge  line  would  be  located 
at  a  higher  elevation  than  the  intake,  owing  to  the  variation  in 
the  level  of  the  water  supply  at  different  seasons.  If  this  varia- 
tion is  only  four  feet,  and  there  is  two  feet  of  water  in  the  intake 
when  the  water  is  at  its  lowest  level,  then  the  overflow  from  the 
hot-well  should  be  6  ft.  from  the  bottom  of  the  intake,  thus  mak- 
ing it  possible  for  the  discharge  waterway  to  cross  the  intake 
waterway  and  leave  at  least  4  ft.  under  the  discharge  waterway 
for  the  intake.  Many  plants  are  arranged  with  the  intake  and 
discharge  waterway  next  to  each  other,  a  practice  the  ultimate 
economy  of  which  iss  doubtful,  there  being  a  slight  saving  in  con- 
struction cost  which  is  counterbalanced  by  loss  in  operation 
owing  to  the  rise  of  temperature  of  the  intake.  If  a  surface  con- 
denser is  to  be  installed  both  waterways  should  be  kept  at  the 
same  level  regardless  of  the  variation  in  the  height  of  the  water 
supply,  and  in  this  case  a  considerable  saving  in  the  cost  of  con- 
struction would  result  if  the  two  waterways  are  placed  in  the  same 
trench. 


322 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


Class  19  —  Condenser  Cooling  Water ;  Branches  to  and  from 
the  Cooling  Tower.  The  various  makes  of  cooling  tower  are  all 
quite  similar  in  their  general  construction  and  operation.  Details 
shown  in  Fig.  265  (Ic/-i)  are  common  to  all  makes.  The  water 
is  distributed  over  the  tower  filling  at  the  top  and  allowed  to 
percolate  through  the  filling  downward  against  the  rising  current 
of  air.  The  different  forms  of  filling  furnished  by  the  manu- 
facturers of  water  towers  are  ordinarily  rated  at  i  to  1.125  scl-  ft- 


FIG.  265. 

of  cooling  surface  per  pound  of  steam  condensed,  and  the  cost  of 
the  cooling  tower  materials,  not  including  the  foundations,  brick 
lining,  motor  to  drive  the  fan  nor  cost  of  erection,  is  generally  from 
10  to  14  cents  per  square  foot  of  cooling  surface.  The  height  of 
the  tower  is  generally  about  32  or  33  ft.,  measured  from  the  top  to 
the  bottom  of  the  metal  casing.  The  metal  casing  is  lapped  so 
that  the  water  will  not  leak  through  the  seams. 

The  lowest  section  of  the  casing  would  ordinarily  be  not  less  than 
0.25  in.  and  the  top  section  not  less  than  0.125  m-  thick.  The 
distributor  is  supported  on  hollow  brass  balls,  and  the  bearing 
surfaces  of  the  sleeves  at  the  end  of  the  discharge  pipe  are  of  brass 
to  insure  that  the  distributor  will  revolve  with  but  very  slight 
pressure  at  the  nozzles.  The  I-beams  shown  to  support  the  filling, 
rest  on  the  brick  lining.  The  air  at  the  base  of  the  tower  being 
under  a  slight  pressure,  the  water  seal  shown  is  required  where 
the  water  is  discharged  from  the  tower  to  a  storage  basin,  as  it  pre- 


CONDENSER   COOLING   WATER   PIPING.  323 

vents  air  from  passing  through  this  opening.  The  size  of  fan 
required  does  not  appear  to  be  standardized  among  the  different 
manufacturers,  as  those  supplied  vary  from  two  8-ft.  to  two  lo-ft. 
fans  to  supply  the  draft  for  a  tower  for  30,000  Ib.  of  steam  per 
hour. 

Different  manufacturers  employ  different  materials  for  the 
cooling  surfaces.  The  most  commonly  used  material  is  wood, 
the  most  satisfactory  wood  for  this  purpose  being  swamp  cypress, 
in  surfaced  boards  i  in.  by  8  in.  set  on  edge  about  1.5  in.  apart. 
Each  layer  is  laid  at  right  angles  to  the  one  below  it.  Glazed  tile 
is  also  used,  unglazed  tile  being  very  unsatisfactory  due  to  its 
moisture  absorbing  capacity.  This  causes  the  unglazed  tile  to 
freeze  and  crumble  in  cold  weather  when  the  tower  is  not  in  opera- 
tion. 

Another  material  which  is  quite  satisfactory  for  rilling  is  galvan- 
ized wire  screening.  These  are  hung  from  the  top  'in  such  a 
manner  that  they  can  be  easily  removed  and  replaced  when  they 
are  eaten  out.  The  chief  advantage  of  the  wire  screen  construc- 
tion is  that  it  offers  the  least  possible  resistance  to  the  flow  of  air 
through  it,  making  it  possible  to  cool  the  water  by  natural  air  draft 
instead  of  by  the  use  of  a  fan.  This,  in  itself,  is  quite  a  saving,  as 
it  requires  i  hp.  for  each  1,000  Ib.  of  steam  per  hour  which  is  con- 
densed, or  about  2  per  cent  of  the  power  developed  by  the  main 
engine.  For  instance,  about  35  hp.  is  required  to  drive  the  fan 
for  a  2,ooo-hp.  engine.  To  avoid  the  expenditure  of  this  power  it 
would  be  economy  to  invest  $125  for  each  horsepower  saved,  or, 
in  other  words,  for  a  plant  as  stated,  an  expenditure  of  $4,375 
additional  for  a  natural  draft  tower  would  be  justified.  This  would 
be  five  times  the  outlay  required  to  pay  the  difference  in  cost  of 
the  two  systems.  The  saving  in  power  would  unquestionably 
pay  the  difference  in  yearly  cost  of  maintaining  wire  screens  in 
good  order.  In  considering  natural  draft  cooling  towers,  it  should 
be  especially  noted  what  duty  would  be  required  of  the  circulating 
pumps  to  determine  whether  they  would  require  more  or  less  power 
owing  to  the  elevation  to  which  the  water  must  be  pumped. 

The  ideal  system  is,  of  course,  to  raise  the  water  the  least  possible 
distance  and,  at  the  same  time,  use  natural  draft.  Fig.  266 
(19-2)  shows  the  cooling  tower  arranged  for  natural  draft  and  the 
distance,  a,  reduced  to  the  least  possible  amount.  This  tower  is 
shown  of  rectangular  construction  instead  of  round,  as  in  Fig.  265, 


324 


STEAM   POWER   PLANT  PIPING  SYSTEMS. 


as  the  rectangular  form  would  be  more  suitable  where  it  is  neces- 
sary to  support  it  on  the  roof.  The  reason  for  placing  this  form 
of  tower  on  the  roof  is  to  insure  a  better  circulation  of  the  air  and 
also  because  the  air  farther  from  the  ground  is  somewhat  cooler. 

If  a  surface  condenser  is  used,  the  relative  height  of  the  tower 
with  respect  to  the  condenser  is  of  no  importance  in  determining 
the  power  required  to  handle  the  circulating  water,  as  the  high 


FIG.  266. 


suction  and  discharge  columns  balance  each  other,  and  the  power 
required  for  circulating  the  water  is  simply  determined  by  the 
distance  a.  A  surface  condenser,  using  water  thus  cooled,  would 
require  about  40  Ib.  of  circulating  water  per  pound  of  steam  con- 
densed, and  if  a  centrifugal  pump  belted  to  the  main  engine  shaft 
were  employed  its  efficiency  would  be  about  40  per  cent.  Hence 
100  ft.-lb.  would  be  expended  in  raising  the  required  volume  of 
water  i  ft.  Assuming  the  engine  to  be  using  18  Ib.  of  steam  per 
horsepower  per  hour,  the  power  needed  to  circulate  the  cooling 
water  would  be  1,800  ft.-lb.  per  hr.,  or  30  ft.-lb.  per  min. 
approximately,  or  o.ooi  hp.  for  each  engine  horsepower,  for  each 
foot  the  water  is  lifted  in  the  distance  a.  This  would  justify  an 
expenditure  of  $0.125  Per  nP-  f°r  each  foot  of  a.  If  the 
plant  had  a  i,ooo-hp.  unit,  the  expenditure  of  $125  for  the  reduc- 
tion of  each  foot  of  the  distance  a  would  be  justified. 
A  jet  condenser  can  be  used  with  economy  in  conjunction  with 


CONDENSER   COOLING    WATER   PIPING. 


325 


a  cooling  tower  only  when  the  tower  is  located  so  that  the  hot-well 
discharge  will  flow  without  any  appreciable  loss  of  head  directly 
on  to  the  cooling  surface  filling,  and  the  circulating  pump  raises 
the  water  from  the  basin  of  the  cooling  tower  up  and  into  the 
injection  pipe  to  the  lower  end  of  the  column  of  water  which  the 
vacuum  will  support. 

The  design  shown  in  Fig.  265  would  require  about  a  3o-ft.  lift 
and  the  jet  condenser  about  7  ft.,  making  a  total  of  37  ft.  which  the 
water  would  have  to  be  raised.  This  would  require  approximately 
0.037  hp.  per  horsepower  of  the  main  engine.  If  the  water  could 
be  taken  from  the  cooling  pond  the  loss  of  head  through  the  tower 
would  be  eliminated,  thus  making  the  power  required  for  the 
condenser  but  0.7  hp.  per  100  hp.  of  the  engine. 

The  surface  condenser  is  better  suited  for  operation  with  the 
cooling  tower,  as  it  can  be  located  at  almost  any  elevation  and 
avoid  any  head  loss  other  than  that  required  at  the  cooling 
tower  and  the  friction  head  of  the  piping 
system.  There  are  many  installations,  how- 
ever, using  elevated  cooling  towers  and  the 
suction  type  of  jet  condenser,  as  shown  in 
Fig.  267  (19-3).  This  makes  a  very  inefficient 
installation.  The  head  on  the  injection  pipe 
is  entirely  wasted,  being  resisted  by  closing 
the  injection  valve  at  the  condenser.  The 
distance  from  the  pump  to  the  outlet  at  the 
top  of  the  cooling  tower  is  frequently  as 
much  as  60  ft.  Assuming  18  Ib.  steam  per 
hp.-hr.  of  the  main  engine  and  40  Ib.  of  cir- 
culating water  per  pound  of  steam  condensed, 
and  a  pump  requiring  120  Ib.  of  steam  per 
hp.-hr.  and  having  an  efficiency  of  60  per 
cent,  we  find  that  the  circulating  pump  re- 
quires 24.2  Ib.  of  steam  for  each  100  Ib.  of  steam 
delivered  to  the  main  engine.  In  other  words, 

the  condenser  pump  requires  as  much  steam  to  . 

FIG.  267  (19-3). 
operate  it  as  is  saved  by  operating  the  engine 

condensing.     It  may  be  that  a  slight  economy 
is  secured  in  such  an  instance,  due  to  the  auxiliary  exhaust  steam 
being  delivered  to  the  feed  water  heater,  but  the  question  is,  why 
is  not  apparatus  which  is  suited  to  each  particular  installation 


326  STEAM  POWER  PLANT   PIPING  SYSTEMS. 

employed?  By  using  a  surface  condenser  and  the  distance  a, 
10  ft.,  the  steam  consumption  of  the  condenser  pump  would  be 
but  one-sixth  as  great  as  in  the  preceding  case,  or  about  4  Ib.  of 
steam  for  each  100  hp.  delivered  to  the  engine.  This  steam, 
however,  would  be  condensed  in  the  heater  and  the  heat  returned 
to  the  boiler,  thus  a  very  good  return  on  the  investment  in  the 
cooling  tower,  condenser,  etc.,  would  be  secured. 

The  heat  required  to  operate  the  pump  would  be  about  four 

184 
times  46  B.t.u.  and  the  engine  100  Ib.  at  913  B.t.u.,  or,  —       =  0.2 

s     3 

B.t.u.  for  the  condenser  for  each  100  B.t.u.  required  by  the  main 
engine. 

The  most  conspicuous  loss  in  the  operation  of  condensing 
machinery  in  conjunction  with  cooling  towers  is  that  occasioned 
by  the  long  water  line  between  the  cooling  tower  and  the  con- 
denser, these  lines  invariably  having  a  large  number  of  turns 
and  restricted  passages.  In  fact,  this  difficulty  is  also  conspic- 


uous in  the  condenser;  in  receiving  bids  on  the  condenser 
this  point  should  be  given  careful  consideration,  as  the  differ- 
ence in  cost  of  different  apparatus  may  be  deceiving,  the  higher 
price  being  oftentimes  the  cheaper  when  the  cost  of  operation  is 
considered.  If  the  lines  between  the  cooling  tower  and  the 
condenser  are  -long,  it  is  always  good  practice  to  increase  their 
size,  as  the  fixed  yearly  cost  on  the  difference  on  the  investment 
is  less  than  that  saved  in  the  operation.  Pipe  bends  should  be 
used  in  place  of  elbows,  as  each  elbow  in  a  i2-in.  line,  for 
instance,  is  equivalent  to  about  40  ft.  of  pipe.  The  piping  is 
oftentimes  'made  more  compact  by  using  elbows  of  short  radius, 
etc.,  as  shown  in  Fig.  268  (19-4)  for  condenser  No.  i,  but 
the  resistance  in  the  line  of  piping  is  thereby  increased.  The 
loss  by  friction  of  water  flowing  through  the  system  shown  in 


CONDENSER   COOLING   WATER   PIPING.  327 

No.  2  is  no  greater  than  that  shown  in  No.  i.  The  losses  occa- 
sioned by  short  radius  ells  and  square  ends  at  the  pipe  inlets  and 
outlets  makes  the  avoidable  losses  of  No.  i  amount  to  about 
300  ft.  of  pipe  if  it  is  12  in.  in  diameter.  This  saving  is  suffi- 
cient in  itself  to  permit  running  the  line  to  the  top  of  the  roof  or 
an  outdoor  cooling  tower  and  not  show  so  great  a  friction  loss  as 
that  of  the  short  connected  system  shown  in  No.  i. 

The  amount  of  water  lost  by  evaporation  in  the  cooling  operation 
varies;  systems  using  cooling  trays  with  air  circulating  under  them 
require  less  than  that  necessary  for  boiler  feeding,  being  as  low 
as  0.5  Ib.  loss  by  evaporation  for  each  pound  of  steam  condensed. 
This  system  requires  a  very  large  tray  surface,  as  its  operation  is 
dependent  upon  radiation  only.  Systems  in  which  the  air  is  passed 
through  the  water  require  much  less  surface,  as  the  heat  is  taken 
up  by  evaporation  as  well  as  by  radiation.  This  style  of  water- 
cooling  will  lower  the  temperature  as  much  as  15  degrees  below 
that  of  the  surrounding  atmosphere,  a  reduction  in  the  tempera- 
ture of  the  water  of  as  much  as  50  degrees.  With  50  degrees 
difference  in  temperature  the  amount  of  cooling  water  required 
would  only  be  about  20  Ib.  per  Ib.  of  steam  condensed.  If  the 
loss  is  7  per  cent,  then  1.4  pounds  of  cooling  water  would  be 
evaporated  for  each  pound  of  steam  condensed.  In  regular 
practice  it  has  been  found  that  the  water  fed  to  the  boiler  is 
sufficient  at  all  times  to  provide  for  the  evaporation,  this  being 
due  possibly  to  the  fact  that  when  the  load  is  very  light  the  fans 
would  not  be  used,  thus  reducing  the  loss  by  evaporation,  the 
cooling  by  radiation  to  the  air  passing  through  the  tower  by  its 
natural  draft  being  then  sufficient  to  cool  the  water.  In  cold 
weather  it  is  generally  necessary  to  draw  off  a  portion  of  the 
cooling  water,  as  the  evaporation  is  then  less  than  the  water  fed 
to  the  boiler;  this  being  the  case  where  the  cooling  water  is  not 
used  for  boiler  feeding. 


CHAPTER    XIX. 
CONDENSATION,    AIR    AND    VACUUM    LINES. 

Class  Jl  —  Condensation  and  Air  Line  from  Condenser.  Sur- 
face condensers  and  elevated  jet  condensers  can  easily  be  arranged 
to  remove  the  air  separately  by  what  is  termed  a  dry  vacuum 
pump.  Such  a  pump  is  designed  to  handle  air  only,  and  the 
usual  construction  is  similar  to  the  crank  and  fly  wheel  type 
of  air  compressors.  The  piston  speed  of  this  type  of  pump  is 
generally  high,  400  ft.  per  min.  being  approximately  the  normal 
speed.  The  clearance  is  reduced  to  the  least  possible  amount 
and  in  many  other  ways  the  pump  is  designed  especially  for 
compressing  air,  and  if  by  accident  even  a  small  amount  of  water 
is  drawn  into  the  pump,  it  is  liable  to  be  damaged.  The  total 
piston  displacement  of  a  dry  vacuum  pump  is  generally  greater 
than  the  total  displacement  of  the  water  circulating  pumps,  but 
seldom  exceed  it  by  more  than  50  per  cent.  The  amount  of 
air  discharged  by  a  dry  vacuum  pump  is  only  a  small  portion 
of  the  piston  displacement,  and  because  of  the  expansion  of  the 
air  contained  in  the  clearance  spaces,  compression,  resistance  of 
the  valves,  ports,  etc.,  the  quantity  discharged  varies  from  10  to 
15  per  cent  of  the  piston  displacement. 

The  different  types  of  condensers  either  permit  of  or  require  a 
different  method  of  handling  the  air  or,  more  correctly  speaking, 
the  non-condensable  vapor.  In  a  jet  condenser,  these  vapors  are 
mingled  with  the  circulating  water  and  if  the  water  contains 
organic  matters,  the  volume  to  be  handled  would  be  very  much 
greater  than  in  a  surface  condenser.  Though  the  elevated  jet 
type  of  condenser  would  have  the  greater  amount  of  air  to  remove 
it  requires  less  special  provision  for  removing  the  air  than  the 
surface  condenser. 

There  are  many  elevated  jet  condensers  which  are  maintaining 
a  vacuum  of  25  and  26  in.  which  have  no  provision  made  for  the 
removal  of  air  other  than  that  of  the  downward  flowing  column 
of  cooling  water,  having  only  centrifugal  pumps  to  maintain  the 

328 


CONDENSATION,    AIR   AND    VACUUM   LINES.  329 

vacuum.  Condensers  of  this  type  are  generally  constructed  the 
same  as  an  ejector  with  the  water  and  the  steam  meeting  in  a 
restricted  passage,  both  having  a  downward  flow  at  the  point  of 
meeting.  Owing  to  the  velocity  of  the  mixture  of  steam  and  water 
through  the  restricted  passage,  the  air  which  reaches  a  condensing 
chamber  is  carried  downward  through  the  tail  pipe  together  with 
the  circulating  water  and  is  discharged  into  the  hot  well. 

The  velocity  of  the  water  in  the  tail  pipe  varies  from  250  ft. 
to  500  ft.  per  min.  being  greater  in  large  than  in  small  condensers. 
By  using  a  dry  vacuum  pump  on  large  size  condensers,  it  is  possible 
to  maintain  a  high  vacuum,  say,  26  or  27  in.  and  requires  only 
sufficient  water  to  condense  the  steam,  thus  increasing  the  tem- 
perature of  the  hot  well  water,  which  is  desirable  if  it  is  to  be  used 
for  boiler  feeding. 

Though  this  saving  is  conspicuous  in  the  larger  sizes,  it  is 
doubtful  whether  there  are  any  advantages  attending  the  use  of 
dry  vacuum  pumps  on  condensers  smaller  than  16  in.  diameter 
of  exhaust. 

There  is  a  special  design  of  elevated  jet  condenser  which  employs 
two  tail  pipes,  one  being  restricted  in  size  and  designed  for  a  high 
water  velocity  to  eject  the  air  and  discharge  it  into  the  hot  well. 
The  other  tail  pipe,  which  is  of  sufficient  size  to  carry  away  all  the 
water  which  the  ejection  pipe  will  not  discharge,  has  its  opening 
from  the  condenser  bowl  at  a  higher  elevation  than  the  ejection 
pipe  opening.  A  condenser  designed  on  this  principle  is  shown  in 
Fig.  269  (Ji-i)  and  it  has  been  claimed  that  a  vacuum  of  26  and 
27  in.  has  been  maintained  with  a  high  temperature  of  the  water 
in  the  hot  well,  and  no  other  means  provided  for  removing  the  air 
other  than  the  air  ejection  tail  pipe.  This  being  the  case,  but 
very  little  additional  machinery  and  apparatus  is  required  with 
this  condensing  arrangement,  the  circulating  pump  being  any 
one  of  the  standard  low  pressure  designs,  the  one  which  is  most 
flexible  and  efficient  bein'g  a  direct  connected  engine  type  cen- 
trifugal pump,  the  exhaust  of  which  is  piped  to  the  feed  water 
heater. 

The  dry  vacuum  pump  is  not  wholly  necessary  with  surface 
condensers,  but  unlike  the  elevated  jet  condenser  some  provision 
must  be  made  for  removing  the  air  with  a  pump,  either  of  the 
wet  or  dry  vacuum  type.  Air  that  accumulates  in  a  surface  con- 
denser is  in  the  compartment  together  with  the  condensation  and 


330 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


in  no  way  comes  in  contact  with  the  circulating  water.     The 
movements  of  the  condensations  are  comparatively  slow,  and  not 

sufficient  to  remove  the  air.  The 
air  may  be  taken  together  with  the 
water,  or  separately,  as  shown  in 
Figs.  28  and  29.  The  wet  vacuum 
pump  is  that  most  generally  used 
and  is  so  termed  because  it  handles 
the  air  together  with  the  con- 
densation. This  class  of  pump  is 
also  used  for  the  suction  type  jet 
condensers  to  remove  the  air  and 
condensation,  and  when  so  used  is 
generally  styled  an  "air  pump." 
The  class  of  service  is  practically 
the  same  for  both  condensers,  the 
jet  condenser  having  approximately 
thirty  times  as  much  water  to 
handle  and  a  correspondingly 
greater  amount  of  air.  The  action 
of  this  combined  air  and  water 
vacuum  pump  is  somewhat  peculiar, 
its  jerky  motion  not  being  gener- 
ally understood.  Fig.  270  (Ji-2) 
shows  the  wet  vacuum  pump  at- 
tached to  a  condenser.  When  the 
pump  is  in  regular  operation,  but 
little  condensation  is  being  handled, 
and  that  is  well  down  in  the  suction 
pipe.  When  the  pump  is  dis- 
charging the  contents  of  the  water 
end,  one  side  is  under  pressure 
marked  +  and  the  other  side  is 
at  the  same  pressure  as  the  con- 
denser and  is  marked  -.  The 
pressure  behind  the  steam  cylinder 
is  also  under  pressure  marked  +, 


FIG.  269  (Ji-i). 


this  pressure  being  maintained  sufficiently  high  to  overcome 
the  pressure  on  the  water  end  marked  +.  The  work  per- 
formed in  compressing  the  contents  in  the  water  cylinder 


CONDENSATION,   AIR  AND    VACUUM  LINES. 


331 


marked  +  is  similar  to  compressing  a  spring.  The  air  con- 
tained in  the  water  cylinder  being  the  elastic  body,  as  soon 
as  the  steam  valve  has  crossed  over  the  port  and  allowed  the 
exhaust  port  to  communicate  with  the  end  of  the  cylinder  that 
has  been  under  compression,  the  support  in  the  steam  cylinder 
is  taken  from  the  end  of  the  piston  rod,  and  the  compressed  air 
in  the  water  end  marked  +  is  free  to  expand,  thus  causing  the 
quick  recoil  so  conspicuous  in  this  class  of  machinery.  The 


FIG.  270  (Ji-2). 

recoil  movement  will  reach  almost  the  full  stroke  when  the  pump 
is  running  above  speed,  and  when  there  is  no  recoil  the  pump 
is  taking  only  water,  the  air  in  this  case  accumulating  in  the  con- 
denser and  by  keeping  the  steam  from  the  condensing  surfaces, 
reduces  its  capacity  and  as  the  capacity  becomes  less  than  that 
required  to  condense  the  steam  delivered  to  the  condenser,  the 
vacuum  drops. 

The  amount  of  air  that  is  being  handled  can  easily  be  judged 
by  the  amount  of  recoil.  The  amount  of  recoil  necessary  for 
successful  operation  can  only  be  determined  by  observing  the 
vacuum,  as  the  volume  of  air  is  largely  dependent  upon  the  tight- 
ness of  the  piping,  stuffing  boxes,  etc.  When  the  amount  of 
recoil  of  the  pump  piston  reaches  nearly  the  full  stroke,  it  is  an 
indication  that  there  are  air  leaks  which  should  be  located  at  once 
and  made  air  tight.  This  is  in  many  cases  a  very  difficult  opera- 
tion, both  the  locating  of  the  leak  as  well  as  to  close  them  after  they 
have  been  found.  One  of  the  most  positive  methods  of  showing 
up 'the  leaks  is  to  fill  the  vacuum  system  with  water  and  put  a 
slight  pressure  on  it,  about  10  pounds  to  the  square  inch,  and 


332  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

while  the  pipes  are  filled  with  water  make  a  careful  inspection  oi 
the  entire  system,  marking,  or  drawing  up  all  joints  and  stuffing 
boxes  where  leaks  are  found.  In  case  the  exhaust  pipes  are 
large,  it  may  be  necessary  to  place  posts  under  the  pipe  to  support 
the  additional  weight,  as  10  ft.  of  24-in.  pipe  will  contain  about 
3,000  Ib.  of  water.  Another  method  of  locating  leaks  in  the 
system  is  to  create  a  low  vacuum  on  the  system,  say  five  pounds, 
and  with  a  small  pointed  brush,  shellac  the  joints,  observing  care- 
fully where  the  shellac  is  drawn  in.  Many  of  the  small  leaks  can  be 
closed  in  this  manner,  but  where  large  leaks  are  found  it  may  be 
necessary  to  make  a  new  joint.  Another  method,  but  quite  crude, 
is  to  give  all  the  joints  a  heavy  coat  of  pitch,  while  the  vacuum  is 
maintained  on  the  system,  trusting  that  the  pitch  will  fill  up  the 
cracks  and  stop  the  leaks. 

If  gas  is  obtainable  at  the  plant  the  entire  piping  system  can  be 
filled  with  gas  and  leaks  located  by  a  candle  passed  around  the 
joints.  The  quantity  of  gas  necessary  would  not  be  expensive, 
1,000  cu.  ft.  being  sufficient  to  fill  a  large  system,  say  140  ft.  of 
pipe  3  ft.  in  diameter.  To  fill  a  line  with  gas,  it  is  necessary  to  fill 
it  with  steam  and  then  close  up  the  system,  and  as  the  steam  con- 
denses allow  gas  to  fill  the  pipe. 

Considerable  trouble  is  experienced  with  the  use  of  metallic 
packing  for  piston  rods,  valve  stems,  etc.,  on  account  of  the  air 
leaking  past  them.  The  piston  rod  packing  can  be  improved  by 
carefully  removing  it  from  the  stuffing  box  and  marking  the  parts 
so  they  will  go  back  in  place.  The  high  spots  should  then  be 
carefully  scraped  so  that  they  exactly  fit  the  rod  and  thus  assist  the 
packing  to  wear  down  to  a  perfect  bearing.  The  motion  of  the 
parts  of  the  packing  is  quite  slight,  and  as  they  are  made  to  wear 
slowly  an  air-tight  fit  may  not  be  secured  for  a  considerable  time 
if  the  operator  waits  for  it  to  wear  to  a  perfect  fit,  and  if  the  leak 
is  very  serious,  it  would  probably  never  wear  tight,  as  the  wear 
caused  by  the  leakage  would  exceed  that  of  the  rod  and  therefore 
the  leak  would  become  larger  instead  of  smaller.  The  low- 
pressure  cylinders  are  subjected  to  such  low  temperatures  that 
almost  any  form  of  fibrous  packing  may  be  used  for  them  success- 
fully. Fibrous  packing  may  require  more  frequent  attention  and 
renewal  and  may  eventually  cost  more  than  metallic  packing,  but 
since  the  loss  of  vacuum  is  often  2  in.  in  the  case  of  metallic  pack- 
ings, which  are  apparently  in  good  condition,  the  fibrous  packing 


CONDENSATION,   AIR   AND    VACUUM  LINES.  333 

will  probably  be  the  most  economical  unless  the  packing  manu- 
facturers will  guarantee  to  install  and  maintain  the  packing  so 
that  it  will  remain  as  tight  as  fibrous  packing. 

Each  inch  of  vacuum  loss  is  equivalent  to  about  i  per  cent 
increase  in  the  cost  of  operation,  which  would  amount  to  about 
$440  a  year  in  the  case  of  i,ooo-hp.  engine  operating  12  hr.  a  day. 
The  cost  of  packing  and  expense  of  keeping  it  in  good  condition  is 
small  compared  to  the  loss  caused  by  a  drop  in  the  vacuum.  Stuff- 
ing boxes  should  be,  if  possible,  arranged  so  that  either  fibrous  or 
metallic  packing  can  be  used,  and  the  engine  should  preferably  be 
so  arranged  that  the  change  from  metallic  to  fibrous  packing  and 
the  renewal  of  packing  can  be  made  without  dismantling  the  engine 
or  interfering  with  its  regular  hours  of  service. 

Class  J2,  3,  4  and  5  —  Dry  Vacuum  Mains  and  Branches.  A 
dry  vacuum  main  is  necessary  where  there  is  more  than  one  con- 
denser and  more  than  one  dry  vacuum  pump,  as  it  permits  the  use 
of  one  pump  on  one  or  both  condensers.  The  mains  should  be 
tapped  at  the  top  for  branches  from  the  condenser  and  the  pump 
connection  should  be  taken  from  the  bottom.  This  detail  is  quite 
important  to  insure  the  draining  of  all  condensation  to  be  removed 
from  the  main  through  the  air  pumps  in  a  small  continuous  volume. 
There  is  no  objection  to  passing  the  condensation  through  the 
pump  if  it  is  in  the  form  of  mist,  as  it  aids  in  reduction  of  the  com- 
pression temperature  in  the  air  pump  cylinder,  but  it  is  unsafe  to 
allow  the  condensation  to  enter  the  air  pump  in  slugs,  for  the  air 
pump  would  undoubtedly  be  seriously  damaged,  as  the  piston 
speed  is  high  and  the  clearances  small.  The  probable  result  would 
be  a  broken  cylinder  head,  valves,  connecting  rod  or  other  part. 

The  dry  vacuum  main  should  have  a  slight  uniform  pitch  toward 
the  air  pump  opening  to  prevent  the  accumulation  of  condensation 
in  pockets  and  a  valve  on  the  pump  suction  should  be  located 
directly  below  the  main  as  shown  in  Fig.  271  (j2-i).  This 
arrangement  avoids  the  possibility  of  the  branch  filling  with  con- 
densation down  to  the  valve,  a  detail  which  will  not  permit  of 
draining  on  account  of  the  line  being  under  less  pressure  than  the 
atmosphere.  The  valve  between  the  pump  branches  is  necessary 
so  that  repairs  can  be  made  to  the  main  while  the  condenser  on  the 
other  side  of  the  valve  is  in  operation.  The  valves,  a,  located  close 
to  the  air  pump,  should  not  be  less  than  one-fourth  the  diameter  of 
the  pump  suction,  and  they  should  be  of  the  globe  form  to  insure 


334 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


tightness.  These  valves  are  necessary  in  starting  the  pump,  to 
permit  it  being  brought  up  to  speed  before  the  full  vacuum  is  put 
on  it.  After  the  pump  is  in  operation  the  branch  line  valves  should 
be  opened  slowly  so  as  to  permit  the  water  which  has  accumulated 
above  them  to  leak  slowly  past  and  through  the  pump.  The  tern- 


o 


FIG.  271  (j2-i). 

perature  of  the  air  entering  the  pump  is  generally  about  120  degrees, 
which  is  increased  considerably  by  the  compression  in  the  pump 
cylinder,  so  that  water  jackets  are  necessary  to  keep  the  cylinder 
cool,  as  previously  stated,  under  the  heading  Class  H6.  The 
discharge  from  the  pump  is  quite  dry,  due  to  the  heating  in  the 
cylinder,  and  may  be  discharged  over  an  open  sewer  or  the  like, 
with  some  provision  for  getting  rid  of  the  oil  and  grease  carried 
over  by  the  air.  If  this  air  is  objectionable  in  the  engine  room,  it 
can  be  discharged  into  the  atmospheric  exhaust  line,  as  there  would 
be  practically  no  saving  in  heat  units,  the  temperature  of  the  feed 
water  in  the  heater  being  nearly  as  high  as  the  air. 

The  dry  vacuum  main  and  branches,  as  illustrated  in  Fig.  271, 
may  be  used  for  either  an  elevated  jet  or  a  surface  condenser,  the 
details  being  the  same  in  either  case.  The  elevated  jet  condenser 
discharges  air  together  with  the  tail  water  whether  a  dry  vacuum 
pump  is  used  or  not,  the  dry  vacuum  pump  simply  being  more 
effective,  keeps  the  condensing  chamber  freer  from  air  and  thus 
permits  a  higher  vacuum  to  be  maintained.  The  air  which  is  dis- 
charged through  the  tail  pipe  into  the  hot  well  tends  to  form  vapor, 
hence  if  the  hot  well  is  located  in  the  engine  room  it  should  be 
ventilated,  as  this  hot  vapor  is  generally  very  foul,  being  largely 
the  gas  liberated  by  the  decomposed  matter  carried  in  the  injection 


CONDENSATION,   AIR  AND    VACUUM  LINES. 


335 


water.  Fig.  272  (J2-2)  shows  a  well  ventilated  by  an  air  duct 
which  is  carried  to  the  outside  of  the  building  above  the  grade  line. 
The  manhole  cover  and  the  tail  pipe  should  have  an  air-tight  fit  at 
the  top  of  the  well  to  prevent  the  discharge  of  gases  and  vapor  into 
the  engine  room. 


FIG.  272  (72-2). 

As  previously  stated  the  dry  vacuum  pump  is  a  much  more 
efficient  device  for  removing  the  air  from  the  condenser  than  the 
wet  vacuum  pump  because  of  the  small  clearance  spaces  which 
are  permissible  at  the  cylinder  ends.  In  addition  to  this  they 
have  mechanically  operated  suction  valves,  usually  of  the  form 
shown  in  Fig.  273  (J  2-3).  This  valve  has  a  " flash  port"  pass- 
ing through  it.  The  object  of  this  port  is  to  reduce  the  pressure 
of  the  air  which  remains  in  the  clearance  space  immediately 
after  the  completion  of  the  compression  stroke  and  by  communi- 
cating with  the  opposite  end  of  the  cylinder  increase  the  pressure 
on  the  other  side  of  the  piston  shown  at  b,  which  is  about  to  be 
compressed,  so  that  the  air  can  be  discharged  into  the  atmosphere 
through  the  poppet  valves  shown  in  detail  in  Fig.  274  (72-4). 

These  poppet  valves  should  be  securely  held  in  place,  but  in 
such  a  manner  that  they  will  not  be  burned  in,  as  would  be  the 


336 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


case  if  threaded  and  screwed  into  the  cylinder.  The  valve  proper 
should  be  as  light  and  as  strong  as  possible.  The  best  material 
to  use  for  the  valves  is  bar  steel  or  steel  castings  machined  so  as 
to  reduce  the  weight,  the  shell  of  the  moving  part  being  about 
one-sixteenth  of  an  inch  thick.  The  bridges  shown  in  the  sec- 
tion AB,  Fig.  274,  should  have  at  least  0.25  in.  bearing  to  guide 
the  steel  poppet  valve.  By  making  the  poppet  of  steel  the  valve 


CttJHOf* 


FIG.  273  (J2-3).    . 


FIG.  274  (j2-4). 


faces  will  wear  better  than  if  both  parts  of  the  valve  are  made  of 
brass.  The  set  screw  in  the  cap  should  be  set  firmly  against  the 
valve  and  secured  from  movement  by  a  lock-nut  set  up  tight, 
this  construction  taking  the  strains  without  endangering  the 
small  bridges  in  the  air  port.  The  usual  construction  is  to  place 
the  valve  at  the  side  of  the  cylinder  lying  horizontally.  A  better 
construction  is  to  place  the  valve  at  the  bottom  of  the  cylinder  in 
a  vertical  position,  thereby  reducing  the  wear  of  the  valves  and 
also  insuring  the  pump  against  injury  from  water,  as  the  valves 
located  in  this  position  will  keep  the  cylinder  drained  of  water. 
The  admission  valve  shown  in  Fig.  273  is  mechanically  operated 
to  avoid  the  resistance  offered  by  the  poppet  valve.  The  area  of 
of  this  type  of  valve  must  be  about  6.5  times  that  of  the  discharge 
poppet  valves  to  avoid  throttling  on  the  suction  stroke.  A  back 
pressure  of  one  pound  would  hardly  be  noticed  in  the  discharge, 
but  such  a  drop  through  the  suction  valves  would  materially 
reduce  the  capacity  of  the  pump.  The  capacity  of  the  pump 
would  be  reduced  fully  one-half  and  would  necessitate  a  2-in. 
higher  vacuum  in  the  pump  than  in  the  condenser  to  overcome 
the  resistance  through  the  valves.  By  employing  mechanically 
operated  valves  the  area  of  the  ports  can  be  made  sufficiently 


CONDENSATION,   AIR  AND    VACUUM  LINES. 


337 


large  and  tight  to  avoid  slippage,  which  would  occur  in  large 
poppet  valves  closing  slowly  when  lightly  loaded.  If  a  high 
vacuum,  say  28  in.,  is  desired,  it  is  necessary  to  use  a  dry  vacuum 
pump  or  at  least  a  pump  with  mechanically  operated  suction  valves. 
A  type  of  pump  which  is  now  being  quite  extensively  installed 
for  high  vacuum  service,  which  is  designed  to  handle  air  and 
water  mixed,  is  that  termed  the  suction  valveless  pump  as  shown 
in  Fig.  275  (J2~5).  In  this  design  the  piston  is  pointed  so 
that  it  strikes  the  water  without  shock  and  drives  the  water  of 
condensation  under  the  piston  out  through  the  ports  of  the 
cylinder  at  a  high  velocity,  which  carries  the  air  with  it  on  the 
same  principle  as  an  injector.  The  movement  of  the  piston 
closes  the  ports  and  the  air  and  water  are  discharged  through  the 


FIG.  275  (j2-s). 


FIG.  276  (J2-6). 


head  valves  after  compression.  On  the  downward  stroke  of  the 
pump  a  higher  vacuum  is  formed  in  the  cylinder,  a,  than  exists 
in  the  condenser  at  the  same  instant,  and  the  air  therefore  rushes 
into  the  cylinder  as  soon  as  the  ports  are  uncovered  by  the  piston, 
and  this  is  further  assisted  by  the  injector  action  of  the  water 
which  follows  immediately,  and  as  the  piston  is  moving  very 
rapidly  the  ports  would  probably  be  covered  before  any  back- 
flow  from  the  cylinder  had  a  chance  to  occur.  Be  that  as  it  may, 
however,  the  high  efficiency  and  successful  operation  of  this  type 


338  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

of  pump  is  fully  established  and  demonstrates  its  ability  to 
remove  air  and  condensation  under  a  vacuum  of  28  in. 

The  special  advantages  of  the  suction  valveless  pump  are  that 
it  has  no  bucket  or  foot  valves,  which  constantly  need  care  and 
renewal,  and  are  generally  very  difficult  to  get  at  for  repair. 

It  is  possible  to  use  poppet  suction  valves,  but  in  such  cases 
they  should  be  mechanically  operated,  as  shown  in  Fig.  276 
(J2-6).  Both  suction  and  discharge  valves  are  mechanically 
operated  in  this  pump,  the  operation  of  the  valves  being  accom- 
plished by  the  friction  packing  rings  inside  of  the  discharge  valves. 
In  the  accompanying  illustration  the  suction  valves  are  shown 
open  on  the  upstroke,  the  valve  rods  being  drawn  upward  by 
the  friction,  which  likewise  closes  the  discharge  valves  when  the 
piston  is  on  the  upstroke.  On  the  downstroke  the  friction  of  the 
packing  pushes  the  valve  rods  down,  thus  closing  the  suction 
valves  and  opening  the  discharge  valves.  The  friction  of  the 
packing  rings  must  always  be  maintained  sufficient  to  sustain 
the  weight  of  the  valves  and  valve  rod.  This  arrangement  of 
valves  permits  the  air  and  water  to  be  discharged  and  drawn  into 
the  pump  without  any  appreciable  loss  of  head. 

Class  J6-7-8  and  9  —  Condensation  Main  and  Branches.  This 
class  of  service  pertains  to  surface  condensers  only.  The  con- 
densation alone  or  with  the  air  contained  in  it  may  be  delivered 
to  an  open  heater  by  the  pump  running  continuously  at  a  fixed 
speed,  or  the  pump  may  be  regulated  by  a  float  if  the  pump 
handles  the  condensation  only.  If  the  condensation  pump  is 
governed  by  a  float  it  cannot  handle  air  mixed  with  condensation. 
In  this  case  the  water  of  condensation  may  be  delivered  directly 
to  the  boilers,  as  shown  in  Fig.  226,  through  a  closed  heater,  the 
condensation  pump  in  this  case  being  that  employed  for  feeding 
the  boiler.  With  this  arrangement,  though  extremely  simple,  it 
is  necessary  that  the  pump  be  located  at  a  sufficient  distance 
below  the  condenser  discharge,  so  that  the  weight  of  the  column 
of  water  in  the  pump  suction  pipe  will  be  sufficient  to  raise  the 
valves  of  the  pump  and  completely  fill  the  pump  cylinder  without 
the  necessity  of  maintaining  a  greater  vacuum  in  the  pump 
cylinder  than  in  the  condenser. 

The  details  shown  in  Eig.  276  would  not  be  suitable  for  high 
pressure  such  as  would  be  required  in  boiler  feeding,  and  further- 
more this  detail  could  not  be  employed,  as  the  diameter  of  the  pump 


CONDENSATION,    AIR   AND    VACUUM   LINES. 


339 


necessary  for  boiler  feeding  would  be  far  less  than  is  necessary  for 
the  type  of  valve  construction  there  shown.  For  high  pressures 
the  outside  packed  plunger  pump  is  better  suited,  as  it  is  at  all 
times  possible  to  ascertain  exactly  what  the  leakage  is  and  the  con- 
dition of  the  packing.  In  Fig.  277  (]2-j)  is  shown  an  outside 
packed  plunger  pump,  which  is  packed  by  removing  the  cover 
plate  over  the  suction  chamber,  a.  The  suction  valves  in  this 
pump,  as  will  be  seen  from  an  examination  of  the  drawing,  are 


FIG.  277  (J2-7). 

mechanically  operated  by  the  movement  of  the  plunger  rod,  upon 
which  the  valves  are  mounted.  The  discharge  valves  are  of  the 
usual  heavy  type  employed  for  boiler  feed  pumps.  The  two  brass 
plungers,  which  are  free  to  slip  on  the  rod  within  the  limit  set  by 
the  collars,  bb,  have  valve  seats  turned  on  them  at  their  outside  ends. 
In  operation  the  motion  of  the  pump  rod  is  transmitted  to  the 
plunger  through  the  suction  valve,  which  causes  the  valve  to  be 
firmly  seated  and  kept  tight  by  the  pressure  against  the  end  of  the 
hollow  rams,  and  being  mechanically  opened,  give  free  access  for 
the  water  through  the  suction  end.  A  feature  which  will  be 
evident  from  an  examination  of  the  drawing  is  the  large  suction 
valve  area  presented  by  this  type  of  construction.  This  type  of 
pump  is  especially  suited  for  direct  steam  drive  with  the  steam 
cylinder  at  the  other  end  of  the  piston  rod.  From  its  construction 
it  will  be  easily  seen  that  this  pump  is  well  adapted  to  handle  air 
and  water  together,  but  is  not  suitable  for  use  as  a  dry  vacuum 
pump  on  account  of  the  large  clearances. 

To  insure  a  high  efficiency  the  design  of  a  dry  vacuum  pump 
should  be  of  the  crank  and  fly  wheel  type,  so  that  the  clearances 
may  be  reduced  to  the  least  possible -amount,  as  shown  in  Figs.  275 
and  276.  This  type  of  pump  shown  in  Fig.  277  would  be  more 
efficient  for  handling  air  and  water  combined  if  the  valves  on  the 


340 


STEAM   POWER  PLANT  PIPING   SYSTEMS. 


piston  rod  closed  against  the  other  end  of  the  ram,  closing  against 
the  ram  from  the  same  side  as  shown,  the  valves  being  located 
inside  of  the  ram.  The  air  pumps  shown  in  Figs.  275,  2 76  or  277 
cannot  be  used  if  located  a  considerable  distance  below  the  con- 
denser, as  shown  in  Fig.  226.  For  these  types  of  pump  the  suction 
lines  should  be  carried  from  the  bottom  of  the  condenser  to  the 
suction  chamber  of  the  pump  along  practically  a  level  line,  giving 
the  air  a  free  path  to  the  air  pump  over  the  surface  of  the  water 
in  the  suction  line.  If  it  is  necessary  to  place  a  wet  vacuum  pump 
a  considerable  distance  below  the  condenser,  owing  to  the  use  of 
spring  loaded  suction  valves,  it  is  then  necessary  to  keep  all  the 
water  pumped  out  of  the  suction  pipe  in  order  to  permit  the  air  to 
flow  freely  to  the  pump  cylinder.  This  necessitates  the  pump 
being  run  at  a  higher  speed,  and  by  keeping  the  water  out  of  the 
pump  its  capacity  for  handling  air  is  decreased  as  the  water  is  not 
present  to  fill  the  clearance  spaces.  The  greatest  capacity  for 
handling  air  is  obtained  when  the  water  taken  at  each  stroke  is  just 
sufficient  to  fill  the  clearance  spaces. 

The  condensation  pump  is  oftentimes  located  in  an  out  of  the 
way  place  owing  to  the  position  of  the  condenser,  and,  in  fact,  it 
is  sometimes  necessary  to  set  other  pumps  in  positions  where  it  is 
impossible  to  provide  ready  means  for  observing  their  operation. 
The  most  necessary  operating  condition  to  be  observed  is  the  speed 

at  which  the  pump  is  running. 
This  can  be  easily  ascertained  by 
arranging  an  indicator  at  a  point 
readily  observed  by  the  operator. 
A  simple  detail  for  such  an  indi- 
cator and  one  which  permits  the 
indicator  to  be  placed  in  almost 
any  location  is  shown  in  Fig.  278 
(J2-8).  The  indicator  piping  is 
attached  to  one  end  of  the  steam 
cylinder  or  water  cylinder  and  the 
change  of  pressure  is  noted  by  the 
rise  and  fall  of  the  water  in  the  gage  glass,  there  being  one  movement 
for  each  stroke.  The  upper  valve,  a,  is  kept  closed  while  in  opera- 
tion, the  lower  one  being  open.  The  quantity  of  air  in  the  glass  can 
be  increased  by  manipulating  the  different  valves,  closing  c,  open- 
ing b,  closing  b,  opening  a,  and  drawing  off  the  water  through  e.  To 


FIG.  278  (J2-8). 


CONDENSATION,    AIR   AND    VACUUM   LINES.  341 

raise  the  water  line  have  c  open,  draw  air  at  d  and  close  b,  open  a 
and  discharge  contents  of  glass  as  much  as  required  through  e. 
The  operation  of  this  device  is  due  to  the  air  confined  in  the 
upper  part  of  the  gage  glass,  the  volume  changing  a?  the  pressure 
on  it  changes.  Not  only  can  the  speed  be  observed  with  this  gage 
but  also  the  regularity  of  motion.  The  liquid  in  the  glass  may  be 
colored,  but  for  continuous. service  it  is  better  to  use  clear  water,  as 
nearly  all  colored  liquids  mark  the  glass  where  the  liquid  and  air 
come  in  contact.  It  will  be  better  to  use  galvanized  iron  or  brass 
pipe  and  fittings,  as  they  would  reduce  the  danger  of  the  glass 
becoming  soiled  and  therefore  make  it  possible  to  observe  the 
motion  of  the  water  more  easily. 


CHAPTER    XX. 
CITY    WATER    PIPING. 

Class  Kl  —  City  Water  Main.  Plants  that  are  provided  with 
their  own  water  supply  soon  become  very  careful  in  the  distribution 
and  use  of  city  water.  It  is  only  a  plant  in  which  no  other  than 
city  water  is  obtainable  in  which  the  employees  of  the  plant  become 
wasteful  in  its  use. 

In  laying  out  the  piping  system  of  the  plant  which  is  to  be 
operated  entirely  with  city  water  many  different  methods  can  be 
introduced  which  will  reduce  or  avoid  the  use  of  water.  For 
example,  instead  of  using  hydraulic  turbine  tube  cleaners,  power 
cleaners  should  be  employed,  as  they  are  successful  in  any  plant 
and  especially  so  in  plants  which  use  only  city  water.  Instead  of 
using  furnaces  having  water  cooled  parts  some  other  type  should 
be  used  to  save  the  continuous  loss  of  water.  Instead  of  the  bear- 
ings being  water  cooled  they  should  be  made  sufficiently  large  to 
run  cool  without  water.  Instead  of  ashes  being  dropped  into  metal 
hoppers  or  other  receptacles  which  necessitates  their  being  wetted 
they  should  discharge  into  a  masonry  hopper,  allowing  air  to  the 
grate  to  carry  off  the  heat. 

If  the  water  contains  a  considerable  quantity  of  scale-forming 
salts  it  should  be  treated  chemically  in  a  purifier  in  order  to  reduce 
to  a  minimum  the  quantity  of  water  wasted  in  blowing  off.  Little 
has  been  accomplished  in  the  design  of  an  exhaust  condenser,  a 
device  which  would  save  practically  all  the  water  fed  to  the  boilers 
by  condensing.  Such  a  condenser  would  in  all  probability  be  con- 
structed on  the  same  general  principles  as  an  ejector,  the  ejector, 
however,  having  the  greater  amount  of  work  to  perform,  as  it  takes 
water  from  a  state  of  rest  and  at  a  lower  pressure. 

An  exhaust  ejector  would  take  air  at  practically  the  same  pres- 
sure as  the  air  it  would  discharge  against.  One  cubic  foot  of 
air  requires  0.0686  heat  unit  to  increase  its  temperature  i°  F., 
or,  if  air  is  taken  at  65  degrees  and  delivered  at  205  degrees,  the 
increase  in  temperature  would  be  140  degrees,  which  would 

342 


CITY   WATER   PIPING. 


343 


Hof-  fli'r 


require  9.6  heat  units  per  cubic  foot.  Exhaust  steam  would  have 
965.7  latent  heat  units  per  pound,  and  as  the  volume  at  atmos- 
pheric pressure  is  26.36  cubic  feet 
per  pound  the  exhaust  steam  would 
contain  36.6  latent  heat  units  per 
cubic  foot.  To  condense  i  cu.  ft.  of 
steam  therefore  would  require  3.8 
cu.  ft.  of  air. 

A  system  of  condensing  the 
exhaust  steam  by  means  of  atmos- 
pheric air  is  shown  in  Fig.  279 
(Ki-i ).  The  exhaust  pipe  is  shown 
in  the  center  of  the  air  flue,  the 
object  being  to  increase  the  tem- 
perature of  the  air  to  create  a 
draught.  The  air  would,  however, 
be  drawn  through  the  flue  by  the 
flow  of  steam  through  the  ejector 
flights.  The  upper  section  is  shown 
as  a  water  and  air  separator. 

In  the  arrangement  of  a  con- 
denser of  this  character,  it  must 
be  noted  that  the  exhaust  travels 
at  a  high  velocity,  possibly  5,000 
ft.  per  min.,  and  the  air  at  1,000  ft. 
per  min.,  which  is  quite  rapid,  about 
that  obtainable  by  a  high  stack. 
To  what  extent  the  air  would  be 
accelerated  by  the  exhaust  ejector 
is  quite  problematical  and  to  secure 
the  greatest  difference  in  weight  of 
air  in  the  chimney,  and  that  without, 
it  may  be  advisable  to  place  the 
condenser  at  the  base  of  the 
chimney,  causing  the  entire 
column  of  air  to  be  at  the  high-  pIG>  279  (KI-I). 

est    possible    temperature.     If   the 

capacity  of  the  chimney  is  less  than  the  exhaust  blower  or  ejec- 
tor, then  the  increased  length  of  stack  would  simply  offer  resist- 
ance to  the  flow  of  air,  as  is  the  case  of  a  high  smokestack  placed 


344  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

over  the  fan  of  an  induced  draught  plant.  It  is  quite  probable 
that  the  air  chimney  would  have  to  be  fully  twenty  times  the  area 
of  the  exhaust,  or  about  four  and  one-half  times  the  diameter  of 
the  exhaust  pipe.  The  air  can  be  supplied  from  a  blower,  but  it 
is  very  doubtful  if  the  saving  in  water  expense  would  justify  or 
equal  the  interest  depreciation  and  operating  cost  of  such  an 
arrangement.  A  plant  equipped  with  an  exhaust  condenser 
would  not  require  an  exhaust  heater,  as  it  is  possible  to  feed  the 
cold  make-up  water  into  the  exhaust  condensing  chamber,  thereby 
aiding  the  process  of  condensation  and  heating  the  water.  To 
use  more  water  for  the  purpose  of  condensing  would  be  just  so 
much  water  wasted,  as  there  would  be  no  use  for  it,  and  it  would 
therefore  be  discharged  into  the  sewer.  The  amount  of  water 
added  to  take  the  place  of  that  lost  in  the  form  of  vapor  would  be 
close  to  10  per  cent  of  that  fed  into  the  boilers.  To  prevent  an 
excess  of  air  passing  through  the  chimney,  shown  in  Fig.  279,  it 
is  possible  to  provide  a  thermostat  in  the  return  drip  pipe,  which 
could  operate  a  damper  or  series  of  dampers,  controlling  the 
quantity  of  air  passing  through  the  chimney.  This  would  be 
necessary  to  maintain  the  condensation  at  a  high  temperature 
for  boiler  feeding. 

One  objection  to  such  a  condenser  is  the  increase  of  difficul- 
ties arising  from  cylinder  oil,  as  all  the  oil  is  returned  to  the  boiler 
feeding  system,  but  it  has  the  advantage  of  materially  decreasing 
the  amount  of  scale-forming  salts  admitted  to  the  boiler.  A 
saving  of  fuel  and  water  in  electrical  plants  using  city  water  can 
easily  be  obtained  by  using  motor  driven  auxiliaries  instead  of 
steam  driven  auxiliaries.  The  greatest  difficulty  experienced 
with  motors  for  this  service  has  been  that  only  one  speed  was 
obtainable,  but  there  are  now  a  large  number  of  different  types 
of  variable  speed  motors  on  the  market,  which  have  a  wide  range 
of  speed  with  nearly  a  constant  efficiency.  These  motors  are 
principally  used  to  drive  machine  tools,  some  of  them  having  a 
range  of  5  to  i,  that  is,  the  speed  is  variable  from  full  speed  to 
one-fifth  the  full  speed. 

Plants  which  have  their  own  water  supply  and  are  within 
reach  of  city  waterworks  should  have  a  connection  to  the  city 
main  of  sufficient  size  to  supply  the  boilers.  Invariably  the 
city  connection  is  so  made  that  it  is  a  source  of  loss  to  the  water- 
works. The  most  common  method  is  to  connect  the  city  water 


CITY   WATER   PIPING. 


345 


to  fire  hydrants  and  install  a  meter  at  the  point  where  the  city 
water  enters  the  building,  as  shown  in  Fig.  280  (Ki-2).  The 
system  as  shown  is  primarily  laid  out  for  station  convenience 
and  reliability.  The  fire  hydrants  are  taken  from  a  fire  system 
located  on  the  outside  of  the  building,  fitted  with  a  valve  A,  which 
admits  the  city  water  to  it.  There  is  no  meter  placed  between 
the  city  mains  and  the  hydrants,  partly  on  account  of  the  lia- 
bility of  the  meter  becoming  damaged  under  severe  working 
speeds  and  thus  shutting  off  the  flow  of  water.  As  the  hydrants 


FIG.  280  (Ki-2). 

are  a  protection  against  fire  the  city  is  expected  to  furnish  water 
for  this  service.  The  valves  B  and  C  close  all  connections  into 
the  building  to  prevent  loss  of  pressure  in  case  of  fire  and  damage 
to  .the  inside  piping.  In  regular  operation  it  is  assumed  that 
the  valve  A  is  closed,  B  open,  C  open,  D  closed  and  H  and  F 
open.  This  places  the  outside  fire  lines  and  inside  boiler  and 
miscellaneous  service  line  G  on  the  station  water  system  and  its 
fire  pump  shown  in  the  illustration,  the  only  city  water  being  that 
taken  for  drinking  purposes  and  wash  basins  through  the  valve 
F.  The  assumption  is  that  the  city  water  would  be  used  for  fire 
service  only,  in  case  the  fire  pump  is  thrown  out  of  service,  or,  if 
the  water  supply  of  the  power  plant  fails,  city  water  could  be  run 
into  the  lines  through  the  valve  D.  The  plan  looks  honest,  and 


346  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

if  used  as  stated  it  would  be.  The  chief  engineer  of  the  plant 
knows  how  much  water  has  been  used,  and  if  at  any  time  it 
becomes  necessary  to  stop  the  fire  pump  and  use  city  water,  the 
assistant  is  liable  to  be  reprimanded,  and  consequently  to  obviate 
this  he  would  open  valve  A  and  cut  off  the  pump  at  H,  thus 
allowing  the  city  water  to  flow  around  through  the  fire  mains 
back  to  the  general  main  to  supply  the  boilers  without  register- 
ing on  the  meter.  From  the  operator's  standpoint  there  can  be 
no  objection  to  this  plan  except  that  it  makes  possible  the  presen- 
tation of  an  excessive  water  bill  in  case  the  waterworks  inspector 
should  find  the  valve  A  open.  If  the  station  operator  is  perfectly 
honest  and  does  not  want  to  place  a  means  of  obtaining  city 
water  without  passing  through  the  meter  in  the  hands  of  his 
employees,  he  can  employ  the  following  system  :  The  valve  A 
should  be  sealed  to  prevent  its  being  moved  without  breaking 
the  seal.  The  valve  B  should  be  open  and  valve  D  closed  under 
ordinary  conditions.  The  check  valve  /  prevents  station  pres- 
sure from  backing  into  the  city  lines.  In  this  case  it  would  be 
necessary  to  make  arrangements  with  the  waterworks  regarding  the 
valve  A ,  some  predetermined  damage  being  agreed  upon  which  can 
be  collected  in  case  the  valve  A  is  found  open  at  any  other  time 
than  immediately  after  a  fire,  the  seal  being  the  property  of  the 
waterworks.  The  valves  A,  B  and  C  should  be  located  suffi- 
ciently distant  from  the  building  to  permit  operating  them  in 
case  of  a  fire,  and  if  against  a  wall  they  should  be  a  considerable 
distance  from  windows  or  door  openings  to  permit  access  to 
them.  An  excellent  arrangement  for  placing  valves  A  and  B 
would  be  to  have  a  hose  at  the  fire  department  house  about  50  ft. 
from  the  building  with  the  valve  posts  inside,  or  along  the  side  of 
the  building.  Fire  service  is  seldom  or  never  needed,  and  to 
familiarize  the  employees  with  its  location  and  operation  it  is 
generally  a  good  plan  to  have  the  parts  of  the  fire  system  exposed 
so  that  they  are  constantly  in  sight  of  the  employees. 

Ordinarily  but  one  meter  is  placed  in  a  station,  one  that  is 
large  enough  for  the  ultimate  emergency  requirement,  as  shown 
in  Fig.  280.  If  the  city  waterworks  is  satisfied  with  this  arrange- 
ment it  should  be  satisfactory  to  the  station  operator.  The  small 
line  F  is  oftentimes  but  one-half  or  three-fourths-in.  piping  and 
the  meter  a  3  or  a  4-in.,  with  nothing  flowing  through  it  except 
the  water  passing  through  the  small  line.  The  leakage  past  a 


CITY   WATER  PIPING.  34? 

large  meter  is  sufficient  to  supply  all  or  a  large  part  of  that  used 
from  the  small  line,  and  to  get  the  correct  reading  a  smaller  meter 
should  be  installed  for  ordinary  use  and  the  large  one  for  emer- 
gency service. 

Class  K2  —  City  Water  Connections  to  and  from  the  Meter. 
A  suitable  location  for  the  water  meter  is  sometimes  difficult  to 
find.  The  meter  in  any  case  should  be  properly  protected  from 
frost.  If  located  in  the  basement  of  the  building  it  is  liable  to 
be  subjected  to  low  temperatures  which  injure  the  meter,  and  in 
such  cases  the  meter  should  be  placed  in  a  brick  well  outside  of 
the  building  with  a  tight  cover  over  it,  and  a  small  drain  run 
from  the  bottom  of  the  well  to  a  sewer  or  to  low  ground.  To 
further  protect  the  meter  from  extremely  low  temperatures  straw 
should  be  placed  over  it  to  prevent  air  from  circulating  in  the 
well.  These  meter  pits  are  objectionable,  as  they  are  generally 
damp  and  cause  the  iron  parts  of  the  meter  to  become  rust  eaten, 
and  are  in  inconvenient  places  to  get  into  to  read  or  make  repairs. 
Ordinarily  a  well-constructed  wooden  box  around  the  meter  would 
protect  it  from  the  lowest  temperatures  found  in  the  basement, 
and  if  arranged  so  that  the  box  can  readily  be  removed  repairs 
are  more  easily  made.  To  prevent  freezing  it  is  first  necessary 
to  confine  the  air  surrounding  the  part  to  be  protected,  and, 
second,  to  prevent  the  air  from  circulating  as  far  as  possible. 

If  the  meter  is  placed  inside  of  a  building,  proper  means  should 
be  provided  for  shutting  it  off  and  all  other  inside  piping  to  pre- 
vent waste  of  water  in  case  of  fire.  Such  an  arrangement  is  illus- 
trated in  Fig.  280,  in  which  a  valve  is  shown  outside  of  the 
building.  If  the  water  lines  from  the  meter  carry  only  city  water 
and  have  no  connection  with  any  other  water  supply  system, 
then  the  check  valve  and  stop  valve  on  the  discharge  side  of  the 
meter  is  unnecessary.  If  the  meter  is  constantly  in  service  there 
should  be  a  by-pass  around  it  with  a  valve  in  it  which  can  be 
sealed  by  the  water  department  to  prevent  water  being  drawn 
from  the  system  without  registering  on  the  meter.  A  by-pass  is 
necessary  to  permit  uninterrupted  service  while  repairs  or  adjust- 
ments are  being  made  to  the  meter.  Before  making  such  pro- 
visions, however,  the  details  of  the  arrangement  with  a  sketch 
should  be  submitted  to  the  city  water  department  for  approval. 

Class  K3  —  City  Water  to  Plumbing  Fixtures.  Ordinarily  this 
service  presents  no  unusual  features,  the  most  conspicuous  feature 


348  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

being  that  the  city  water  enters  the  building  quite  cool,  and,  if 
the  lines  pass  through  warm  basements,  the  course  of  the  pipe 
line  is  generally  outlined  along  the  floor  by  the  constant  dripping 
from  the  cold  pipe.  This  difficulty  can  be  overcome  by  burying 
the  pipe  line,  but  in  power  plant  work  the  pipe  lines  are  wherever 
possible  kept  out  of  the  ground  to  facilitate  repairs,  etc.  By 
encasing  the  pipe  with  a  cheap  wool  felt  covering,  the  annoy- 
ance of  sweating  is  overcome  and  at  the  same  time  the  water  is 
thus  kept  at  a  lower  temperature.  The  different  wrought-iron 
pipe  lines  used  for  conveying  water  to  and  from  the  plumbing 
fixtures  should  be  galvanized  to  avoid  as  far  as  possible  the  stain 
caused  by  rust  from  black  pipes,  which  gives  the  plumbing  fix- 
tures a  very  untidy  appearance.  This  point  should  be  observed 
both  for  cold  and  hot  water  lines  to  the  plumbing  fixtures. 

Before  determining  what  faucets  are  to  be  used  for  the  city  cold 
water  it  would  be  advisable  to  ascertain  what  water  is  to  be  used 
for  hot  water  service,  since  it  may  be  found  simpler  to  use  high 
pressure  valves  and  take  hot  water  from  the  feed  main  under 
boiler  pressure.  This  point  is  more  fully  explained  under  Class 
Dio.  The  washstands  in  power  plants  would  become  exceedingly 
dirty  if  some  care  were  not  exercised  over  the  men  using  them,  and 
although  white  enamel  basins  are  difficult  to  keep  clean  they  are 
the  only  kind  that  should  be  used.  Their  untidy  appearance 
assures  that  greater  care  will  be  taken  in  keeping  them  clean. 

Class  K4  —  City  Water  to  Low  Pressure  Water  System.  This 
service  is  shown  in  Fig.  280  and  would  ordinarily  only  be  an 
emergency  connection,  the  regular  service  being  taken  from  the 
station  water  supply.  Such  connections  as  this  are  quite  necessary 
to  insure  continuous  operation,  and  how  to  avoid  the  abuse  of  these 
provisions  is  oftentimes  a  serious  problem.  It  is  a  well-known  fact 
in  station  operation  that  systems  having  two  or  more  means  supplied 
for  meeting  an  emergency  are  not  as  carefully  looked  after  as  those 
having  no  reserve  supplied.  The  result  is  that  where  city  water 
is  connected  to  the  station  system  for  emergency  service  it  is 
generally  quite  extensively  used,  even  though  it  be  at  a  loss  to  the 
company  and  could  to  a  great  extent  be  avoided. 

Possibly  as  effective  a  method  as  can  be  followed  for  reducing 
the  waste  of  city  water  is  to  have  the  water  meter  reading  placed  on 
the  daily  station  log,  showing  from  day  to  day  the  amount  of  water 
used;  also  a  line  from  the  operator  to  state  the  reason  why  the 


CITY   WATER  PIPING. 


349 


valve,  D,  in  Fig.  280,  was  open.  The  most  satisfactory  method  of 
taking  these  readings  is  to  print  the  dials  on  the  record  sheet  and 
let  the  operator  mark  the  position  of  the  pointers,  from  which  the 
chief  engineer  can  figure  the  water  consumption  instead  of  intrust- 
ing it  to  an  assistant.  Mistakes  are  easily  made  in  reading  meters, 
and  if  the  chart  were  used  it  would  reduce  the  possibility  of  error 
to  a  minimum. 

Class  K5  —  City  Water  Connections  to  Boiler  Feed  Main.  If 
the  power  station  has  its  own  water  supply  the  city  water  supply 
should  not  be  connected  with  the  boiler  feed  main.  The  pressure 
carried  on  a  city  main  is  not  sufficient  for  boiler  feeding.  This 
necessitates  joining  the  city  water  connection  to  the  auxiliary  feed 


FIG.  281  (K5-i). 

main.  Here  the  supply  can  be  used  under  a  low  pressure  without 
interfering  with  the  regular  boiler  feeding.  If  the  plant  is  run  with 
city  water  only  then  this  latter  connection  should  be  used,  since  it 
enables  the  operator  to  wash  or  fill  boilers  without  running  any 
pump. 

Fig.  281  (K5~i)  shows  an  auxiliary  main  arranged  so  that 
under  ordinary  conditions  it  will  be  supplied  with  city  pressure  as 
far  as  the  pumps,  thus  making  this  water  available  for  wetting 
down  ashes,  etc.  When  pump  No.  2  is  supplying  the  auxiliary 
main  with  water  under  high  pressure  for  operating  turbine  tube 
cleaners  there  will  be  no  water  at  low  pressure  available  as  far  as 
valve  A.  This,  however,  would  not  be  a  serious  objection  in  most 
boiler  rooms.  To  avoid  damage  to  the  low-pressure  city  lines,  if 
an  operator  should  start  the  pump  without  closing  the  valve,  A,  a 
check  valve,  B,  should  be  fitted  in  the  low-pressure  main,  as  shown. 

Feed  water  can  in  an  emergency  be  obtained  by  means  of  a  fire 
hose  if  the  city  fire  plugs  are  properly  located.  This  would  make 


35O  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

the  use  of  city  water  more  troublesome  to  the  operator  and  would 

be  an  evidence  readily  seen  of  his  neglect  in  caring  for  the  system 

that  should  be  in  operative  order. 

Class  K6  —  City  Water  to  Pump  Suctions.     Plants  which  have 

city  water  available  should  have  the  city  service  connection  of 
sufficient  size  to  feed  all  the  boilers.  All  con- 
tinuously operated  plants  should  have  two  separate 
feed  pump  suctions,  whether  there  are  two  different 
sources  of  water  supply  or  only  one.  Plants 
having  both  their  own  and  a  city  water  supply 

Fto  382  (K6-i)    snould  have  the  city  water  Delivered  directly  to  the 
pump  suctions,  as  shown  in  Fig.  282  (K6-i).     It 
is  not  best  to  deliver  the  water  into  the  suction  well,  since  it  may 
be  found  necessary  to  empty  this  well  for  making  repairs. 

The  city  connection  may  be  made  quite  small,  possibly  one- 
third  the  diameter  of  the  regular  suction  pipe.  Water  is  delivered 
through  the  city  lines  under  pressure,  and  such  lines  are  too  seldom 
used  to  justify  a  reduction  of  pipe  line  losses  by  the  use  of  a  large 
pipe.  If  a  plant  is  operated  entirely  on  city  water  there  should  be 
two  separate  city  connections,  as  shown  in  Fig.  283  (K6-2). 
To  provide  this  arrangement  it  may  be  necessary  to  use  two  meters. 
If  two  taps  are  not  provided  the  plant  might  be  without  water  if  the 
city  main  to  which  it  was  connected  should  be  shut  off  for  repairs, 
or  for  any  other  cause.  Fig.  283  shows  a  power  plant  located  at 
the  intersection  of  two  streets  and  connections  made  to  two  mains 
with  two  valves  in  the  city  mains  between  the  connections.  If 
there  were  but  one  valve,  either  A  or  B,  then  it  would  be  necessary 
to  connect  with  the  city  mains  beyond  another  valve,  as  shown  by 
the  dotted  lines  in  Fig.  283.  This  would  necessitate  the  use  of 
another  meter,  also  shown  dotted.  By  connecting  to  the  mains  in 
this  manner  water  is  obtainable  whenever  it  is  necessary  to  shut 
off  the  water  on  both  sides  of  a  city  valve.  The  use  of  two  meters 
permits  a  more  accessible  piping  layout.  It  also  affords  means 
for  repairing  any  part  of  the  main  and  yet  have  one  pump  in 
service. 

The  most  satisfactory  piping  layout  is  one  with  two  separate 
suction  lines  from  the  pump  to  the  water  supply.  A  valve  should 
be  placed  between  these  two  suction  mains  to  separate  them 
whether  water  is  obtained  from  two  city  or  two  private  sources  of 
supply. 


CITY   WATER  PIPING. 


35* 


If  the  suctions  are  taken  from  two  private  sources,  such  as  a 
pond  and  its  tributary  stream,  they  should  be  from  two  points 
which  are  as  far  from  each  other  as  possible.  Thus,,  if  the  stream 
is  muddy  the  suction  can  be  taken  from  the  pond,  or,  if  the  pond 
should  be  empty,  the  suction  can  be  taken  from  the  stream.  If 
water  is  available  from  only  one  source,  such  as  a  small  stream, 


FIG.  283  (K6-2). 

which  is  not  continuously  available  either  because  of  too  little  or 
too  much  water,  which  would  oftentimes  cause  it  to  be  very  muddy, 
then  another  reserve  supply  is  necessary,  either  in  the  form  of  a 
pond  or  an  artesian  well. 

Class  K7  —  City  Water  to  the  Heater.  A  plant  operated 
entirely  on  city  water  would  have  a  connection  to  the  float  con- 
trolling-valve if  an  open  heater  is  used,  in  which  case  this  would 
be  a  regular  service  connection.  If  the  plant  has  its  own  water 
supply  it  will  also  have  a  low-pressure  water  service  and  a  connec- 
tion from  this  low-pressure  service  to  the  heater.  To  supply  city 
water  for  emergency  purposes  it  is  ordinarily  delivered  to  the 
low-pressure  water  mains  which  are  connected  to  the  heater. 

If  these  mains  are  not  properly  laid  out,  necessitating  their 
being  entirely  out  of  service  when  repairs  are  made,  it  will  be 
more  satisfactory  as  regards  reliability  to  connect  the  city  water 
directly  to  the  heater.  This  connection  can  be  a  permanent  pipe 
line,  or  a  temporary  hose  connection  may  be  employed  if  a  hose 
valve  is  attached  to  the  heater.  If  the  valve  is  of  the  proper  size 
to  fit  fire  hose,  the  water  supply  during  periods  of  repairs  can  be 
taken  from  a  fire  hydrant. 


352  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

Class  K8  —  City  Water  to  Fire  System.  The  pressure  carried 
on  city  water  mains  is  generally  low,  about  20  to  30  Ib.  per  sq. 
in.,  and  consequently  when  a  large  number  of  streams  are  taken 
from  a  fire  hydrant  this  pressure  is  almost  entirely  lost  in  over- 
coming the  friction  in  the  pipes.  Power  stations  are  generally 
large  and  high  buildings,  necessitating  the  use  of  high  pressure 
on  the  fire  lines.  If  city  water  only  is  available  for  fire  protection 
it  should  be  connected  to  the  fire  pump  suction,  the  water  at 
such  times  not  passing  through  the  meter.  This  subject  will 
be  taken  up  more  fully  in  "Fire  Protection,"  Class  M. 

Class  K9  —  City  Water  for  Priming  Pumps.  Any  water  may  be 
used  for  priming  pumps,  as  the  quantity  used  is  so  small  that  its 
quality  is  immaterial.  Priming  water  should  be  taken  from  the 
city  mains  only  where  city  water  alone  is  available,  6r  in  plants 
which  have  no  storage  tank  to  furnish  water  for  this  service. 

Class  K1O— City  Water  to  Hydraulic  Elevators.  Water  which  is 
suitable  for  boiler  feeding  is  also  suitable  for  hydraulic  rams,  etc. 
It  would  be  necessary  to  remove  any  loose  sand  from  the  water 
for  either  service.  If  the  plant  is  run  with  city  water  then  the 
ram  should  be  of  such  area  that  the  lowest  city  pressure  would 
operate  it.  The  resistance  of  the  ram  stuffing  box  and  the  loss 
of  head  due  to  the  velocity  of  flow  are  usually  so  great  that  the 
theoretical  pressure  under  the  ram  should  be  twice  that  which  is 
actually  necessary  to  operate  it.  This  subject  will  be  taken  up 
more  fully  in  "  Hydraulic  Elevators  —  Class  O." 

Class  Kll  —  City  Water  to  Engine  Journals.  City  water  in- 
stead of  the  regular  station  water  would  be  used  for  cooling  journals 
if  the  latter  supply  were  too  warm  to  be  effective.  Rather  than 
use  city  water  it  would  be  more  economical  to  use  a  greater  quan- 
tity of  the  station  water.  If  city  water  has  a  temperature  of  fifty 
degrees  F.  and  the  station  water  is  fifteen  degrees  warmer  and 
the  discharge  from  the  journals  has  a  temperature  of  150  degrees 
F.,  then  the  city  water  is  raised  100  degrees,  whereas  the  station 
water  is  raised  85  degrees.  This  difference  in  practically  all  such 
cases  is  too  slight  to  justify  the  use  of  city  water. 

If  city  water  is  used  exclusively  then  it  should  be  discharged 
into  a  drip  main  located  so  that  the  water  will  drain  into  the  heater. 
Funnels  should  be  fitted  so  that  the  drip  flow  may  be  observed. 
If  the  heater  is  located  too  high  to  permit  the  use  of  a  gravity  dis- 
charge, the  sights  may  be  made  air-tight,  as  shown  in  Fig.  284 


CITY   WATER  PIPING.  353 

(Kn-i),  permitting  a  back  pressure  on  the  engine  journals, 
sights,  etc.  To  avoid  the  loss  of  the  air  confined  in  the  glass  body 
such  sights  should  be  placed  where  there  is  the 
least  pressure. 

Another  method  of  determining  the  flow  is  to  use 
in  addition  to  the  regulating  valve  a  three-way  valve, 
one  discharge  being  into  the  heater  and  the  other 
into  an  open  funnel  connected  to  the  sewer.  To 
determine  the  amount  of  water  flowing  the  valve  can 
be  turned  to  discharge  into  the  funnel,  and  again 
placed  in  its  normal  position,  thus  turning  the 
discharge  into  the  heater. 

Class  K12  —  City  Water  to  the  Damper  Regulators.  If  no 
other  water  of  constant  pressure  is  available  to  operate  the  damper 
regulators,  city  water  may  be  used  for  this  service.  Especially  is 
this  true  if  the  pressure  is  low,  say  about  thirty  Ib.  per  sq.  in.  The 
use  of  boiler  feed  water  or  steam  condensation  is  extremely 
objectionable  due  to  the  destructive  effect  on  the  controller  valves. 

The  working  piston  of  a  regulator  should  be  of  sufficient  diam- 
eter and  stroke  to  operate  the  dampers  while  under  low  pressure. 
The  work  of  moving  the  damper  must  be  done  by  one  stroke,  the 
return  of  the  damper  being  effected  by  a  counterweight.  There- 
fore the  capacity  of  the  regulator  cylinder  must  be  twice  that 
necessary  to  move  the  damper  alone.  If  a  force  of  forty  Ib.  is 
required  to  move  the  damper  when  in  any  position,  then  the  effec- 
tive capacity  of  the  regulator  cylinder  should  be  eighty  Ib.,  or  twice 
this,  which  would  be  about  150  Ib.  pressure  on  the  piston  rod.  If 
the  lowest  pressure  on  the  water  main  from  an  overhead  tank  is 
fifteen  Ib.,  the  regulator  would  require  a  piston  about  3.5  in.  in 
diameter,  a  much  larger  size  than  the  manufacturers  of  regulators 
care  to  furnish.  However,  if  constant  and  satisfactory  service  is 
desired  low  pressure  must  be  used. 

Class  K13  —  City  Water  to  Pressure  Oil  Tanks.  Water  is  fre- 
quently used  to  raise  cylinder  oil  from  its  storage  tank  through 
pipe  lines  into  the  lubricators.  Almost  any  supply  will  perform 
this  duty  satisfactorily.  If  engine  oil  is  being  put  under  pressure 
by  means  of  water  it  is  quite  essential  that  a  fairly  uniform  pres- 
sure be  maintained.  If  the  station  has  a  gravity  water  storage 
tank,  then  a  more  uniform  pressure  is  obtainable  by  connection 
to  the  storage  tank  than  can  be  had  by  using  city  water. 


354  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

Class  K14  —  City  Water  for  Drinking  Purposes.  Drinking 
water  supply  is  a  service  that  cannot  be  dispensed  with,  and  though 
every  other  service  is  supplied  from  the  station  pumping  system  it 
is  generally  necessary  to  use  the  city  water  for  drinking.  It  may 
be  that  the  station  water  is  cleaner  and,  in  fact,  may  " sparkle," 
but  yet  it  may  have  properties  which  affect  the  employees  of  the 
power  house,  more  particularly  if  they  are  accustomed  to  city  water. 
Considerable  time  would  be  saved  if  a  drinking  place  were  located 
near  the  firemen  and  another  convenient  for  the  engineers. 

These  pipe  lines  should  be  of  galvanized  iron  carried  under- 
ground and  exposed  to  the  heat  of  the  building  as  little  as  possible. 
In  all  probability  this  piping  connection  can  be  installed  without 
passing  the  water  through  the  large  station  meter.  This  will 
require  paying  the  regular  water  rate.  By  making  proper  provision 
in  this  regard  but  little  time  and  water  are  lost  when  an  operator 
goes  for  a  drink.  If  a  pipe  runs  100  ft.  or  more  through  a  hot 
room  the  station  employees  are  apt  to  let  the  water  run  for  a  con- 
siderable time  until  sufficient  cold  water  has  been  wasted  to  cool 
the  hot  pipes.  Drinking  water  is  as  important  in  a  power  plant  as 
the  feed  water  for  the  boilers,  and  should  be  given  the  fullest  con- 
sideration. 

Class  K15  — City  Water  to  Other  Buildings.  Whether  the 
water  for  the  different  shops,  barns,  etc.,  is  to  be  taken  through  the 
power  station  meter  depends  largely  upon  how  complete  an  account- 
ing system  is  employed.  Ordinarily  it  is  much  more  satisfactory 
to  have  a  separate  record  of  the  water  used  in  the  power  station 
and  that  used  in  the  shops,  and  if  sprinkling  cars  are  operated 
possibly  a  separate  record  also  of  the  water  used  for  this  service. 
If  the  city  water  department  will  not  install  so  many  small  meters 
they  can  be  installed  by  the  consumer  and  placed  in  separate 
buildings.  This  permits  calibrating  them  and  using  them  as  a 
check  on  the  main  meter. 


CHAPTER   XXL 
ARTESIAN    WATER    PIPING. 

Class  LI  and  2  —  Artesian  Water  to  Pumps  and  Water  Tanks. 

The  use  of  artesian  wells  is  not  as  general  as  the  advantages  accom- 
panying their  use  warrant.  The  question  of  water  supply  should 
be  the  first  to  receive  consideration  in  deciding  upon  a  site  for  a 
power  station.  The  coaling  facilities  can,  as  a  rule,  be  more 
easily  provided  than  a  suitable  water  supply.  A  surface  water 
supply,  such  as  a  creek  or  stream  which  gives  ample  water  for  9 
or  10  months  and  runs  dry  a  month  or  two,  is  of  little  use  as  a 
source  of  water,  since  it  is  necessary  to  provide  some  other  source  of 
supply  for  the  remaining  portion  of  the  year. 

The  cost  of  raising  water,  say  100  feet,  from  a  driven  well  is  not 
excessive  if  the  pump  is  motor-driven.  In  this  case  the  pump 
discharges  against  a  5o-lb.  head.  Allowing  for  friction,  each 
theoretical  horsepower  costs  but  approximately  one-half  cent  per 
hour  if  the  plant  is  equipped  with  compound  condensing  engines. 
One  thousand  horsepower  of  capacity,  assuming  a  steam  con- 
sumption of  20  Ib.  of  stean  per  hp.  per  hn,  would  require 
20,000  Ib.  of  water  per  hour,  or  333  Ib.  per  min.  If  this  is  raised 
100  ft.,  the  theoretical  work  done  is  at  a  rate  of  approximately 
33,300  ft.-lb.  per  min.,  or  i  horsepower.  If  the  efficiency  of  the 
pumping  plant  is  50  per  cent  the  actual  horsepower  delivered  to 
the  pumps  will  have  to  be  twice  the  theoretical,  thus  making  the 
cost  of  pumping  the  water  required  by  i,ooo-hp.  plant  for  one 
hour  about  one  cent.  This  is  assuming  that  the  water  is  allowed 
to  discharge  into  a  cooling  pond  in  which  the  loss  by  evapora- 
tion is  equal  to  the  water  required  for  feeding  the  boiler. 

At  the  cost  just  estimated  for  the  i,ooo-hp.  plant  the  cost  of 
pumping  1,000  gal.  of  water  would  be  0.004166  cent,  a  cost  which 
is  much  lower  than  that  for  which  any  waterworks  system  can  sell 
water.  The  cost  of  repairs  and  depreciation  must  be  added  to  these 
figures.  Regarding  the  capacity  of  a  deep-well  pump,  it  should 
be  borne  in  mind  that  it  should  be  at  least  twice  the  normal  load 

355 


356  STEAM   POWER   PLANT  PIPING   SYSTEMS. 

capacity;  that  is,  if  333  pounds  of  water  are  required  per  minute, 
the  pumps  should  not  have  a  capacity  of  less  than  666  pounds  per 
minute.  This  additional  capacity  is  required  to  permit  the  storing 
of  water  for  emergency  purposes  or  to  supply  the  plant  while  repairs 
are  being  made.  Motor-driven  pumps  can  have  a  stroke  of  24  in., 
but  to  have  a  long  life  they  should  not  make  over  35  strokes  per 
minute,  which  would  require  a  5-in.  water  cylinder  to  supply  the 
i,ooo-hp.  capacity  as  stated. 

In  determining  the  size  of  the  deep-well  pumps  required,  the 
capacity  of  the  plant  upon  which  the  capacity  of  the  pump  is  based 
should  not  be  the  average  horsepower  as  determined  from  the  horse- 
power-hours daily  output  of  the  plant.  For,  a  plant  may  have 
engines  of  2,ooo-hp.  capacity,  but  develop  only  20,000  hp.-hr.  in 
20  hours;  in  which  case  the  pump  should  have  an  hourly  capacity 
sufficient  for  2,000  hp.,  this  being  twice  the  average  output.  Ordi- 
narily the  pump  should  have  a  capacity  equal  to  the  steam  machin- 
ery installed,  and  some  system  of  water  storage  should  be  provided 
—  one  of  considerable  capacity,  so  that  if  the  deep-well  pump 
should  be  out  of  service  for  two  or  three  days  no  shortage  of  water 
will  be  encountered. 

If  the  condensers  discharge  into  a  cooling  pond  this  pond  would 
be  of  ample  capacity,  since  it  would  ordinarily  have  10  sq.  ft.  of 
cooling  surface  for  each  pound  of  steam  condensed  per  hour.  A 
drop  in  the  water  level  of  i  foot  would  therefore  furnish  sufficient 
water  to  supply  the  plant  for  62  hr.  or  three  days.  This  does  not 
include  seepage  losses,  a  waste  which  must  be  considered  when 
determining  the  capacity  of  pumping  machinery.  If  the  pond  is 
built  in  clay  or  lined  with  clay,  the  seepage  loss  will  be  quite  slight. 
There  are  many  storage  ponds  constructed  on  ground  20  feet  or 
more  above  that  surrounding  them,  which  are  used  to  store  the 
rain  and  melted  snow  which  fills  them  during  the  early  spring  for 
use  during  the  summer  months.  Water  stands  in  these  ponds  with 
but  little  drop  of  level,  this  drop  being  caused  more  by  evaporation 
than  by  seepage. 

It  may  be  desirable  to  put  in  an  overhead  tank  to  supply  the 
low-pressure  mains,  but  this  is  of  no  practical  use  for  a  reserve 
water  supply  for  boiler  feeding  unless  the  plant  is  exceedingly 
small.  For  instance,  a  plant  of  1,000  boiler  hp.  would  require  a 
tank  of  about  40,000  gal.  capacity  to  run  10  hr.  Forty  thousand 
gallons  is  equivalent  to  5,000  cu.  ft.  or  a  tank  would  be  required 


ARTESIAN   WATER   PIPING. 


357 


10  by  20  by  25  ft.,  weighing  65  tons  when  filled  with  water.  If 
there  is  no  cooling  or  other  pond  where  water  can  be  stored,  then 
a  cistern  may  be  constructed  in  the  ground,  the  sides  and  bottom 
being  finished  with  cement  concrete,  much  the  same  as  a  cement 
floor  or  sidewalk. 

If  water  from  the  city  waterworks  is  available  a  large  storage 
tank  is  not  so  essential,  but  if  in  any  case  a  storage  tank  must  be 
provided  it  should  be  in  connection  with  the  deep-well  pump,  so 
that  the  latter  can  be  discharged  continuously  for  a  long  period 
without  being  compelled  to  work  in  unison  with  the  other  pumps. 
The  deep  well  is  generally  located  a  considerable  distance  from 
the  plant,  and  by  using  storage  tanks  of  five  hours'  capacity  of  the 
deep-well  pump,  it  will  avoid  starting  or  stopping  the  pump 
except  at  long  intervals.  If  an  induction  motor  is  used,  started 
by  a  switch  in  the  engine  room,  and  the  storage  tank  is  located 
where  it  can  be  seen  from  the  power  house,  a  telltale  must  be 
provided  so  the  operator  can  ascertain  when  the  reservoir  is 
filled.  The  device  shown  in  Fig.  285  (Li-i)  permits  the  deep 


p<///^^ 

FIG.  285  (Li-i). 

well  and  storage  tank  to  be  located  at  some  distance  from  power 
house.  The  standpipe  in  the  power  station  has  a  telltale 
attached,  which  can,  if  desired,  be  fitted  with  an  electric  high 
and  low  water  alarm,  brought  into  contact  by  the  telltale.  The 
automatic  high  and  low  water  alarm  should  require  little  or  no 
attention.  This  form  of  telltale  is  the  most  approved  automatic 
indicator,  since  it  has  no  work  to  do  but  make  and  break  the  bell 
circuit,  which  notifies  the  attendant  to  open  or  close  the  pump 
motor  switch.  This  requires  possibly  one-half  minute  of  the 
attendant's  time  every  five  hours  or  so.  The  connection  from 
the  storage  system  to  the  power  house  should  be  of  ample  size, 
say  twice  the  size  of  the  pump  suction,  in  order  to  insure  the 
water  level  in  the  telltale  being  approximately  the  same  as  that 
in  the  cistern.  As  there  would  be  no  appreciable  pressure  on  it, 


358  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

such  a  line  of  piping  could,  in  almost  every  case,  be  constructed 
of  sewer  tile.  Tile  pipe  would  not  be  desirable  if  the  cistern 
water  level  were  above  the  ground  level. 

To  insure  the  telltale  showing  correctly,  a  small  pipe,  say  one 
inch,  may  be  laid  in  the  same  trench  with  the  pump  suction  and 
be  used  merely  to  operate  the  telltale,  thus  permitting  the  use  of 
a  smaller  metal  suction  pipe.  An  ideal  power  station  arrange- 
ment is  secured  if  the  storage  cistern  or  pond  is  built  upon  a  hill 
high  enough  so  that  the  water  from  the  cistern  will  be  under 
sufficient  head  to  serve  the  low-pressure  water  service  in  the  power 
house,  shops,  etc.  The  feed  pumps  taking  this  water  under 
pressure  would  avoid  the  difficulties  caused  by  air,  etc.  The 
pressure  corresponding  to  an  elevation  of  from  20  to  25  ft.  is 
generally  sufficient  for  any  service  other  than  boiler  feeding. 


FIG.  286  (Li-2). 

It  is  quite  immaterial  where  the  storage  tank  is  located.  If 
the  desired  head  is  obtainable  by  placing  the  storage  tank  500  ft. 
or  perhaps  more  from  the  power  house,  it  would  be  better  prac- 
tice than  to  maintain  a  pump  in  operation  simply  for  supplying 
the  low-pressure  system.  A  power  station  which  has  its  storage 
cistern  located  on  a  hill  is  shown  in  Fig.  286  (Li-2). 

The  artesian  well  is  very  seldom  found  within  the  power 
station,  though  there  is  no  reason  why  it  should  not  be,  and  there 
are  many  good  reasons  why  it  should  be  in  the  main  building,  as 
the  cost  of  the  pump  house  would  be  dispensed  with.  Further, 
being  in  a  high-roofed  room  it  would  be  very  easy  to  remove  the 
pump  rods  from  the  casing  or  raise  the  casing  itself  if  necessary. 
The  reason  that  artesian  wells  are  generally  located  in  separate 
buildings  is  that  designs  for  the  power  house  are  completed, 
decided  upon,  and  work  on  the  power  house  started  before  work 
on  the  deep  well  is  undertaken.  If  a  deep  well  and  its  driven 


ARTESIAN   WATER   PIPING.  359 

head  are  to  be  located  in  the  main  building,  it  is  necessary  to 
decide  this  point  long  before  work  is  started  on  the  buildings  in 
order  that  the  well  drillers  may  complete  their  work  and 
remove  their  drilling  derrick  before  work  on  the  buildings  is 
started. 

In  order  to  avoid  having  the  well  interfere  with  the  location  of 
some  other  machinery,  it  is  absolutely  necessary  that  its  location 
be  very  carefully  considered  before  the  well  drilling  is  started. 
Such  is,  however,  not  the  general  method  of  doing  things. 

In  most  cases  the  well  is  not  located  and  the  contract  is  not  let 
until  the  water  is  absolutely  needed.  It  is  because  of  the  order 
of  doing  things  that  the  artesian  well  is  located  outside  the  power 
house,  not  that  it  is  not  wanted  inside,  but  simply  because  it 
would  seriously  delay  the  construction  work.  When  drilling  a  well 
a  steam  line  should  be  run  from  the  power  house  to  the  driller's 
outfit,  rather  than  rely  upon  the  small  vertical  boiler  of  the  lat- 
ter's  apparatus.  Much  time  and  money  can  be  thus  saved  by 
avoiding  delays,  etc. 

In  sinking  wells,  it  is  found  perfectly  practicable  to  use  out- 
side connected  couplings,  when  casing  is  driven  through  the  loose 
earth  only.  When  rock  is  reached  the  casing  is  allowed  to  set 
upon  it,  and  the  drilled  hole  is  made  the  size  of  the  bore  of  the 
casing  pipe,  no  casing  being  used  through  the  rock  unless  a  great 
depth  is  to  be  reached.  In  this  event  the  casing  pipe  is  reduced 
in  size  and  is  passed  through  the  rock,  as  shown  in  Fig.  287 
(Li~3).  The  joints  in  the  lower  casing  are  made  as  shown  in 
detail  in  this  figure.  The  purpose  of  the  casing  through  the 
rock  is  to  prevent  loose  pieces  of  rock  from  falling  into  the  drilled 
hole.  In  many  instances  the  rock  can  be  drilled,  leaving  a  clean 
hole  without  the  use  of  the  casing. 

Whenever  it  is  possible  to  place  the  pumping  cylinder  in  the 
upper  or  larger  casing,  this  is  done,  since  it  permits  the  use  of  a 
larger  cylinder.  To  be  able  to  reach  water  of  a  lower  elevation 
and  not  to  be  compelled  to  reduce  the  working  cylinder  to  suit  the 
size  of  the  smaller  casing  pipe,  the  pump  suction  with  a  strainer 
at  its  lower  end  is  carried  down  a  full  length  of  the  pipe,  about 
20  ft.  There  is  no  danger  of  this  strainer  striking  the  bottom  of  the 
well,  since  it  is  invariably  sunk  considerably  deeper  than  abso- 
lutely necessary,  possibly  50  ft.  or  so  below  the  pump  cylinder. 
How  much  deeper  it  is  sunk  than  necessary  to  obtain  water  depends 


360 


STEAM  POWER   PLANT  PIPING   SYSTEMS. 


upon  the  performance  of  the  well  and  the  judgment  of  the  well 
driller,  whose  judgment  is  generally  accepted. 

The  pump  cylinder  is  attached  to  the  drop  pipe,  as  shown  in 
Fig.  288  (Li-4),  the  bore  of  the  cylinder  being  about  0.25  in. 
less  than  the  bore  of  the  drop  pipe,  to  permit  removal  of  the  pump 
piston  or  foot  valve.  Cup  leather  packings  are  universally  used 


FIG.  287  (Li-3). 


FIG.  288  (Li-4). 


for  these  pumps.  The  drop  pipe  does  not  rest  on  its  lower  end, 
the  pipe  being  fixed  at  its  upper  end  and  left  hanging  free  from 
this  upper  support.  Fig.  289  (Li~5)  shows  a  drop  pipe 
supported  from  the  pump  head.  The  cap  A  is  removable  to 
permit  the  removal  of  the  sucker  rod,  piston  or  valves  when 
necessary  without  disturbing  the  pipe  connections.  If  the  drop 
pipe  is  to  be  removed  it  can  be  done  by  disconnecting  the  bearing  B 
and  the  joint  C  without  unscrewing  any  pipe  work.  Ordinarily 
the  base  of  the  pump  head  is  fixed  at  the  top  of  its  foundation  and 
the  upper  portion  is  arranged  to  slide  back  out  of  the  way.  The 


ARTESIAN   WATER   PIPING. 


361 


FIG.  289  (Li-s). 


use  of  a  drop  pipe  is  the  most  approved  practice  for  the  construction 
of  artesian  wells,  and  only  in  emergency  cases  should  the  locked 
cylinder  be  used. 

If  a  well  having  an  abundant  supply  of  water  is  fitted  with  a 
pump  of  insufficient  capacity,  there  are  two  methods  of  increasing 
the  capacity  of  the  pump.  The  stroke 
may  be  increased  or  the  diameter  of  the 
pump  may  be  increased.  The  best 
method  is  to  increase  the  stroke.  A 
i6-in.  stroke  pump  is  ordinarily  run  at 
30  strokes  per  minute  or  at  a  plunger 
speed  of  480  in.  per  min.,  and  a  pump 
with  a  36-in.  stroke  would  ordinarily 
operate  at  20  strokes  or  720  in.  per 
minute,  a  gain  in  capacity  of  50  per  cent. 
If  an  8-in.  casing  is  used  a  5. 7 5 -in. 
cylinder  would  be  used  with  a  drop 
pipe,  and  if  it  is  of  the  locked  form 
about  a  7.25-in.  cylinder  would  be  used, 
giving  about  60  per  cent  increased 
capacity.  By  increasing  the  stroke  as  well  as  the  diameter  the 
capacity  of  the  pump  can  be  increased  nearly  two  and  one-half 
times. 

There  are  numerous  types  of  locked  cylinders  which,  if  they 
become  too  securely  locked,  would  probably  have  to  stay  whether 
or  not  they  leaked  between  the  cylinder  and  the  casing.  Such 
makeshifts  may  be  justified  in  the  case  of  an  emergency,  but 
should  be  avoided  in  designing  new  work.  The  locked  cylinder 
is  lowered  into  the  casing  and  locked  or  packed  to  the  driven 
casing,  no  drop  pipe  being  used  in  this  case.  The  cylinder  in  this 
case  is  made  as  large  as  can  be  lowered  through  the  driven  casing. 

For  power  station  use  motor-driven  artesian  well  pumps  are  far 
superior  to  steam-driven  pumps,  as  they  are  more  economical  to 
operate  and  are  in  many  ways  less  troublesome. 

Class  L3  —  Artesian  Water  to  Power  House.  If  the  artesian 
well  water  is  the  only  available  water  for  the  power  house,  some 
means  should  be  provided  for  a  double  supply.  This  is  necessary 
not  only  to  make  repairs  but  to  insure  water  for  operation  in  case 
some  part  of  the  system  should  give  out  and  require  being  thrown 
out  of  service.  Fig.  290  (L3~i)  shows  a  storage  cistern  and 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


well  connected  to  opposite  ends  of  the  suction  main.  If  it  became 
necessary  to  shut  off  the  main  from  the  well  to  the  pump  or  from 
the  storage  cistern  to  the  pump,  it  could  be  done  without  inter- 
fering with  the  other  supply. 

A  relief  valve  should  be  placed  in  the  discharge  line  from  the 
deep-well  pump  without  any  valve  between  it  and  the  pump. 
This  relief  valve  would  ordinarily  protect  the  deep-well  pump  and 
permit  the  excess  water  to  return  to  the  well  when  the  storage 
tank  is  shut  off  from  the  feed  pump,  and  the  latter  necessarily 
takes  water  from  the  deep-well  pump  direct.  Provided  the  storage 


8 
i, 


FIG.  290  (L3-i). 

cistern  is  sufficiently  elevated  to  give  the  desired  head,  the  low- 
pressure  system  should  be  piped  as  shown,  so  that  its  service  will 
not  be  interrupted  if  either  the  pump  or  tank  should  be  shut  off. 
If  the  storage  cistern  is  at  a  low  elevation  so  that  the  feed  pumps 
take  water  by  suction,  then  one  of  the  feed  pumps  could  provide 
the  low-pressure  water  using  the  auxiliary  feed  main  for  the  low- 
pressure  supply. 

Pump  suction  lines  are  essential  for  continuous  operation,  and 
the  plant  in  no  case  should  be  made  wholly  dependent  upon  any 
one  pipe  connection  for  its  continuous  operation.  The  under- 
ground pipes  should  be  of  cast  iron  the  same  as  that  used  for 
city  water  pipes.  A  telltale  pipe  can  be  run  from  the  storage 
reservoir  to  the  power  station,  as  shown  in  Fig.  290  and  also  in 
Fig.  285,  the  pipe  being  laid  in  the  same  trench  as  the  supply  pipe 
instead  of  independently,  as  shown. 

Class  L4  —  Artesian  Water  to  Other  Buildings.  Ordinarily 
the  buildings  located  near  the  power  plant  are  supplied  with 


ARTESIAN   WATER  PIPING.  363 

water  from  the  low-pressure  general  service  main  or  the  fire  main 
if  the  latter  is  intended  to  serve  for  both  the  general  and  the  fire 
service.  The  water  for  the  plumbing  fixtures  in  the  power  house 
and  other  buildings  when  taken  from  the  general  low-pressure  main 
should  not  be  considered  to  be  in  any  particular  class  of  water 
supply  if  there  is  more  than  one.  For  instance,  the  low-pressure 
system  may  be  supplied  with  deep  well  water  to-day,  storage 
cistern  water  to-morrow,  and  perhaps  with  city  water  the  next  day. 

The  distribution  of  water  from  its  original  source  should  be 
considered  only  with  respect  to  the  systems  served  and  not  by 
the  apparatus  itself.  For  example,  Fig.  290  shows  a  system  of 
supplying  artesian  water  to  the  storage  tanks,  the  pumps  and 
the  low-pressure  main.  The  services  supplied  from  these  sources 
do  not  belong  to  the  artesian  water  system,  but  solely  to  the  system 
which  takes  artesian  water  when  it  can  get  it  and  other  water  when 
artesian  water  is  not  obtainable. 

Class  L5  —  Artesian  Water  to  Fire  Mains.  If  a  plant  is  wholly 
dependent  upon  artesian  water  for  its  water  supply,  or  if  there 
is  a  possibility  of  too  small  a  supply  of  water  being  obtained 
from  a  stream,  it  will  be  found  necessary  to  ht>ld  water  in  storage 
for  use  in  case  of  a  fire.  An  artesian  well  may  have  a  capacity 
of  but  60  gal.  per  min.  and  take  16  hr.  to  fill  a  storage  pond  or 
cistern,  yet  together  they  may  make  a  reliable  water  supply  for 
fire  protection.  There  are  cases  where  large  pumps  are  not 
available  for  fire  service,  and  it  is  safer  to  elevate  water  to  a  high 
tank,  say  125  ft.  from  the  ground,  using  a  deep  well  pump  for 
this  service.  For  power  stations  a  better  arrangement  is  to  pro- 
vide a  storage  tank  on  the  ground,  of  much  greater  capacity,  not 
less  than  100,000  gal.,  and  use  a  fire  pump  of  large  capacity. 
This  storage  tank  may  be  arranged  as  shown  in  Fig.  290,  and 
in  case  of  fire  both  feed  pumps  could  be  used  for  fire  service. 

In  this  arrangement  the  pumps  installed  should  be  such  that 
one  is  especially  suited  for  fire  service,  but  applicable  for  boiler 
feeding,  and  the  other  designed  for  boiler  feeding,  but  suitable  for 
fire  service  as  well. 

Class  L6  — Artesian  Water  to  Condensers.  There  are  dif- 
ficulties encountered  in  the  use  of  most  artesian  well  water  which 
appear  conspicuously  in  the  boiler.  The  use  of  such  water  in 
the  condensers  tends  to  diminish  these  difficulties  because  the 
temperature  of  the  water  is  increased,  and  it  is  delivered  to  a 


STEAM  POWER  PLANT  PlPIXG  SYSTEMS. 


large  pond  where  the  solid  matter  contained  in  it  can  settle.  If 
the  jet  type  of  condenser  is  to  be  used,  the  piping  system  can  be 
simplified  by  placing  the  water  storage  tank,  shown  in  Fig.  290, 
so  that  its  extreme  high  water  level  will  be  12  or  18  in.  below  the 
top  of  the  hot-well,  this  ordinarily  being  the  basement  floor  line. 
If  an  elevated  pond  were  employed  to  supply  the  low-pressure 
service,  the  hot-well  would  likewise  have  to  be  elevated,  which 
would  thus  necessitate  the  use  of  an  unsatisfactory  construction. 

Ordinarily  the  reserve  feed  pump  will  likewise  serve  as  a  fire 
pump,  and  if  the  low-pressure  service  is  taken  from  the  fire 
mains  the  pumps  will  always  be  ready  for  fire  service.  In  this 
installation  a  double  system  of  suction  lines  to  the  feed  pumps 
must  be  provided,  and  also  means  must  be  afforded  for  the  feed 
pumps  to  take  water  from  the  hot-well  and  the  fire  pump  to  take 
its  water  from  the  pond,  or,  better  still,  from  the  deep  well  dis- 
charge, the  latter  arrangement  being  shown  in  Fig.  291  (L6-i). 


FIG.  291  (L6-i). 

In  regular  operation  all  the  valves  shown  in  Fig.  291  will  be  left 
open  and  the  check  valve,  a,  will  be  closed.  This  is  because  the 
overflow  of  the  hot-well  will  be  higher  than  the  surface  of  the 
pond  (say  12  in.),  and,  besides,  the  weight  of  the  valve  will  also 
tend  to  close  it. 

The  pump  box  from  which  the  suction  is  taken  should  not  be 
less  than  four  feet  deep,  making  a  distance  of  3  ft.  from  the  pond 
level  to  this  suction,  thus  insuring  water  in  the  suction  line  and 


ARTESIAN   WATER  PIPING,  365 

feed  pumps  at  all  times.  If  water  does  not  flow  to  the  feed  pump 
from  the  condenser  it  will  flow  to  it  through  the  check  valve,  A. 
The  deep  well  water  will  not  regularly  flow  to  the  feed  pump,  but 
will  pass  by  it,  part  being  taken  by  the  fire  pump  working  on  the 
low-pressure  service,  the  remainder  going  to  the  circulating  pump. 
This  will  be  seen  by  examining  Fig.  291.  By  closing  the  valve, 
By  either  half  of  the  suction  system  may  be  shut  off.  If  the  deep 
well  pump  is  operated  together  with  the  feed  pump,  the  excess 
water  will  overflow  at  the  pump  box.  In  the  latter  case  the 
condenser  would  not  be  in  operation.  It  would  be  possible  to 
connect  the  hot-well  to  the  fire  pump,  but  this  would  not  be  used 
enough  to  justify  the  expense  and  increased  complication  result- 
ing from  these  connections. 

Emergency  connections  should  insure  reliability,  and  not 
necessarily  the  highest  economy.  The  system  shown  in  Fig.  291 
will  operate  more  satisfactorily  if  some  form  of  variable  speed 
drive  is  provided  which  will  permit  running  the  pump  at  differ- 
ent speeds. 

To  obtain  drinking  water  a  small  centrifugal  pump  can  be 
placed  either  on  the  end  of  the  motor  shaft  or  belted  from  it. 
This  is  more  advisable  than  to  take  the  drinking  water  from  the 
low-pressure  system  shown  in  Fig.  291,  as  a  low-pressure  line 
would  be  constructed  of  black  pipe  large  in  size,  and  the 
water  would  be  warm,  and  there  would  also  be  danger  of  pond 
water  getting  into  the  low-pressure  service.  This  pump  would 
take  water  from  the  deep-well  pump-discharge  and  would  main- 
tain a  pressure  of  5  or  10  Ib.  Centrifugal  pumps  have  the  advan- 
tage that  they  do  not  require  relief  valves.  The  capacity  of 
such  a  pump  need  not  be  over  10  gal.  per  min.  and  will  require 
less  than  0.25  hp.  to  drive  it. 

If  the  artesian  water  is  to  be  used  for  cooling  a  surface  con- 
denser the  piping  system  would  be  similar  to  that  shown  for  the 
elevated  jet  type  of  condenser  illustrated  in  Fig.  291.  The  con- 
densation then  will  flow  from  the  hot-well  or  base  of  the  con- 
denser to  the  vacuum  feed  pump,  as  in  Fig.  291,  but  the  check 
valve,  a,  will  be  omitted.  If  an  open  heater  is  to  be  installed 
there  must  be  another  pump  to  take  water  from  the  hot- well  and 
deliver  it  to  the  heater;  in  Fig.  291  the  latter  is  indicated  by  d 
and  the  pump  by  c.  This  statement  applies  equally  to  surface 
and  elevated  jet  condensers. 


366  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

Class  L7  —  Air  Lift  for  Artesian  Water.  An  air  outfit  consists 
of  an  air  compressor,  a  pipe  for  conveying  the  air  to  the  bottom 
of  the  well  and  a  device  for  atomizing  the  water  by  air  and  forcing 
the  water  upward,  together  with  the  air  used  for  atomizing. 
The  water  is  raised  in  the  same  manner  as  a  hat  or  piece  of  paper 
is  by  a  high  wind,  the  ability  of  the  air  to  support  or  carry  the 
water  in  reality  depending  simply  upon  the  skin  friction  of  the 
air  on  the  exposed  surfaces  of  the  finely  divided  water.  By 
reducing  the  size  of  a  globule  of  water  by  one-half,  its  area 
becomes  one-fourth  the  original,  but  its  weight  only  one-eighth  of 
what  it  was  previously.  It  is  therefore  evident  that,  the  smaller 
each  particle  of  water  is,  the  greater  will  be  its  frictional  resistance 
in  proportion  to  its  weight.  Consequently,  with  finely  divided 
water  in  an  air  lift  a  smaller  volume  of  air  of  lower  velocity  is 
required  to  create  a  lifting  friction  greater  than  the  weight  of  the 
particles  of  water. 

The  air  lift  can  be  constructed  in  many  different  forms,  but  the 
principle  of  any  design  depends  upon  the  high  frictional  resistance 
of  the  air  on  the  surfaces  of  the  particles  of  water.  The  heavier  the 
particles  of  water  may  be,  the  greater  will  be  the  air  velocity 
required  to  give  the  necessary  lifting  power.  Hence,  the  capacity 
of  the  air  compressor  serving  the  lift  will  depend  upon  how  effec- 
tively the  atomizer  operates.  Further,  as  the  skin  friction  of  air 
increases  approximately  as  the  square  of  the  velocity,  the  higher 
the  velocity  of  the  air  required  the  greater  will  be  the  frictional 
losses  in  the  pipe;  and  for  this  reason  few  air  lifts  show  even  a  fair 
efficiency. 

Obviously,  the  size  of  the  air  discharge  or  water  lift  pipe  must 
be  made  sufficiently  small  to  secure  the  velocity  necessary  to  support 
the  water.  An  air  compressor  having  a  capacity  of  30  cu.  ft.  of 
free  air  per  min.  would  give  a  velocity  of  5,000  ft.  per  min. 
if  the  air  were  discharged  at  atmospheric  pressure  through  a  i-in. 
lift  pipe,  or  a  velocity  of  2,500  ft.  per  min.  if  the  air  is  at  a  pres- 
sure of  15  Ib.  per  sq.  in. 

There  are  two  different  methods  of  delivering  air  to  a  well.  It 
may  be  discharged  through  the  drop  pipe  or  it  may  be  discharged 
through  the  annular  space  surrounding  this  pipe.  Fig.  292 
(Ly-i)  shows  the  air  discharge  taken  from  the  large  drop  pipe. 
This  generally  is  the  better  construction,  since  it  enables  the  use 
of  a  small  pipe  through  which  to  discharge  the  water  and  a  large 


ARTESIAN   WATER   PIPING. 


367 


cross  section  to  furnish  the  air  to  the  lower  end  of  this  pipe.  By 
using  the  drop  pipe  for  the  discharge  a  clear  straight  bore  is  obtained, 
thus  maintaining  more  uniform  conditions  during  the  discharge  of 
the  water. 

It  is  necessary  to  overcome  the  resistance  of  the  piping  and  the 
ejector;  if  15  Ib.  air  pressure  is  to  be  carried,  the  distance,  b,  in 

Fig.  292  should  be 

=) 


made  not  less  than 
35  ft.,  since  the  air 
pressure  in  the 
casing  will  lower 
the  water  level  by 
that  amount.  The 
level,  c-,*is  the  work- 
ing level  of  the 
water  with  the  pres- 
sure removed.  This 

will  be  somewhat  lower  while  the  water  is 
being  pumped  than  while  it  is  standing  at  rest. 
The  distance,  a,  may  be  small  or  it  may  be 
found  better  if  the  ejector  is  dropped  below  the 
standing  water  level.  By  using  a  hose  connec- 
tion at  the  upper  end  of  the  drop  pipe,  and 
making  the  distance,  a,  a  few  inches,  b,  about 
35  ft.,  and  d,  the  length  of  a  pipe,  the  best 
position  for  the  ejector  is  readily  ascertained 
while  the  compressor  is  in  operation.  This 
can  be  done  by  moving  the  drop  pipe  up  and 
down  until  the  most  satisfactory  results  are 
obtained.  The  most  efficient  pressure  at  which 
to  operate  the  lift  can  then  be  easily  determined. 
The  ejector  shown  in  Fig.  292  is  one  com- 
monly used  for  draining  cisterns,  etc.,  and  to 
further  reduce  the  frictional  resistance  of  the 
air  flowing  into  it  holes  may  be  drilled  in  it.  To  obtain  the  best 
results  from  air  lifts,  the  ejector  should  be  ordered  from  a  firm 
which  makes  a  specialty  of  such  devices,  and  in  ordering,  the  exact 
use  to  which  it  is  to  be  put  should  be  stated,  as  the  application 
of  the  ejector  for  this  service  is  different  from  that  for  which  eject- 
ors are  commonly  employed.  The  air  in  this  case  enters  around 


FIG.  292  (Ly-i). 


36$ 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


the  nozzle  instead  of  passing  through  the  nozzle,  as  in  regular 
service. 

If  air  is  available  in  the  plant  for  water  lifting  and  a  special  com- 
pressor is  not  needed  for  this  service  the  air  lift  presents  some  very 
desirable  features,  the  most  important  of  which  is  that  there  is  no 
mechanism  whatever  in  the  well,  and,  further,  it  is  possible  to 
handle  very  large  quantities  of  water  with  it.  These  advantages, 
however,  are  not  ordinarily  sufficient  to  warrant  the  installation  of 
an  air  compressor  especially  for  this  work,  because  a  higher  effi- 
ciency is  obtainable  if  the  common  form  of  deep-well  pump  is 
employed. 

Class  L8  —  Artesian  Water  for  High  Buildings.  In  large  hotels 
and  office  buildings  there  is  ordinarily  a  large  enough  quantity  of 
water  used  to  make  it  profitable  to  sink  a  well.  Buildings  of  this 


FIG.  293  (L8-i). 

class  are  especially  well  adapted  to  artesian  well  work,  because  they 
have  high  open  elevator  shafts  which  permit  of  raising  pump  rods 
and  drop  pipes.  With  an  elevator  in  the  shaft  no  other  apparatus 
is  necessary  to  lift  the  parts  out  of  the  well.  Fig.  293  (L8-i)  shows 
such  a  well  with  the  driving  machinery  set  to  one  side  of  the  well. 
In  this  case  it  would  be  better  to  sink  a  false  casing,  say  20  ft.  long 
and  of  large  diameter,  to  secure  the  soil  under  the  elevator  shaft 


ARTESIAN   WATER  PIPING.  369 

footings.  The  regular  well  casing  should  be  driven  inside  of  the 
false  casing  after  the  latter  has  been  sunk.  The  end  of  the  walking 
beam  can  be  formed  in  the  shape  of  a  Y  with  a  cross-head  pin 
passing  through  the  upper  section  of  the  pump-rod  head.  The 
removal  of  this  pin  and  stuffing-box  cap  only  are  required  to  draw 
out  the  sucker  rod. 


CHAPTER    XXII. 


FIRE    SERVICE    PIPING. 

Class  Ml  —  Fire-Service  Mains.  There  are  two  distinctly 
different  systems  of  fire  protection,  one  being  an  installation  con- 
forming to  the  rules  of  the  fire  insurance  underwriters,  so  that  no 
difficulty  will  be  experienced  in  collecting  insurance,  and  the  other 
an  arrangement  especially  adapted  to  putting  out  fires  which  might 
start  in  the  particular  building  considered,  no  attention  being 
paid  to  the  underwriters'  rules.  Which  of  the  two  systems  is  to  be 
installed  depends  upon  whether  insurance  is  to  be  carried. 

Ordinarily  the  roof  of  a  power  station  is  far  removed  from  any 
inflammable  material  liable  to  set  fire  to  it,  but  in  nearly  every  case 


FIG.  294  (Mi-2). 

there  is  no  protection  for  the  roof,  though  the  latter  is  the  most 
common  fire  loss.  The  roof  is  quite  as  liable  to  be  set  afire  from 
the  top  as  from  the  under  side,  and  to  provide  the  best  protection, 
a  system  such  as  shown  in  Fig.  294  (Mi-2)  would  be  found  valuable 
and  more  particularly  so  if  the  power  house  be  located  close  to 
some  other  building  or  combustible  material.  The  perforated 
spray  fittings  should  be  so  arranged  that  the  trap  door  will  be 
protected  with  water.  Then,  if  necessary,  an  operator  can  get 
on  to  the  runway  in  case  of  fire  around  the  hatch.  A  hose  connec- 

37° 


FIRE   SERVICE   PIPING. 

tion  should  be  provided  on  the  roof,  the  latter  detail  being  shown 
later  under  "fire  service." 

In  considering  fire  protection,  it  is  first  necessary  to  determine 
whether  it  is  simply  to  be  for  the  power  station  or  for  buildings  in 
its  immediate  vicinity.  If  there  are  other  buildings  to  protect,  it 
would  be  more  than  possible  that  they  would  be  insured,  and  to 
secure  the  best  protection  and  insurance  rate  it  probably  would 
be  necessary  to  install  an  underwriters'  fire  pump  in  the  power 
station  so  connected  that  it  would  be  always  ready  for  fire  service 
and  so  arranged  that  all  other  services  taken  from  the  fire  main 
could  quickly  be  shut  off.  In  this  case  it  is  quite  probable  that 
the  fire  pump  would  not  be  connected  to  serve  as  a  reserve  feed 
pump,  thus  requiring  two  feed  pumps  in  addition  to  the  fire  pump. 

Further  to  insure  the  reliability  of  fire  service  it  would  be  advis- 
able to  install  one  of  the  feed  pumps  so  that  it  couhl  be  used  for 
fire  service  if  necessary,  thus  maintain  the  fire  water  supply 
whenever  the  regular  fire  pump  is  being  repacked  or  repaired. 
The  regular  feed  pumps  should  be  of  the  outside  packed-plunger 
type,  the  fire  pump  of  the  underwriters'  type  and  the  second 
feed  pump  of  the  center-packed  plunger  type  with  extremely  light 
rams  to  permit  its  being  operated  at  the  high  speed  necessary  for 
fire  service.  A  fairly  good  arrangement  is  to  use  one  feed  pump 
and  two  fire  pumps  of  smaller  size.  The  latter  plan  is,  however, 
objectionable  if  an  open  feed-water  heater  is  used,  since  the  hot 
water  from  the  heater  will  soon  destroy  the  inside  packing  of  the 
fire  pump,  which  must  be  of  the  piston  pattern  in  order  to  operate 
under  the  high  speed  necessary.  If  the  power  station  is  isolated, 
little  water  is  required  for  its  protection,  and  ordinarily  two  pumps 
will  be  ample.  Both  pumps  could  be  of  the  outside-packed 
plunger  type,  and,  as  all  other  machinery  would  be  stopped  in 
case  of  fire,  these  pumps  could  be  operated  instead  of  one  fire 
pump. 

In  many  plants  the  steam  and  feed  lines  are  supported  from  the 
roof  trusses.  The  only  reason  for  such  an  inconsistent  construction 
is  that  it  is  the  easiest  available  method  of  support.  Not  only 
should  the  lines  be  carried  independently  of  the  roof  trusses, 
but  they  should  be  supported  so  firmly  that  they  will  remain 
intact,  even  if  the  roof  falls  on  them.  The  feed  main  should 
lie  far  enough  below  the  tops  of  the  boilers  to  be  protected  from 
anything  falling  on  it.  The  safety-valve  pipe  through  the  roof 


3/2  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

should  have  the  lightest  obtainable  cast-iron  elbow  at  its  lower 
end  to  protect  the  safety  valve. 

Unless  the  boiler  room  is  protected  against  the  breaking  of  kteam 
lines  in  case  of  fire,  there  should  be  some  special  provision  made 
to  insure  the  continuous  operation  of  the  fire  pump.  The  smoke 
breaching  is  generally  an  easily  destroyed  object  in  case  of  fire, 
and  if  the  fire  pump  is  to  be  kept  running  the  longest  possible 
time,  it  would  be  a  more  certain  arrangement  to  have  a  separate 
underground  fire  pump  connection  to,  say,  two  different  boilers, 
one  always  being  in  service.  In  case  of  fire  over  the  boilers  the 
connections  to  these  would  be  opened  and  all  others,  including 
those  of  the  boiler  feed,  water  columns,  etc.,  closed.  The  fire 
pump  in  this  case  should  be  in  a  separate  building  outside  the 
power  house,  or  walls  should  be  built  around  it  so  that  it  could 
be  operated  even  though  the  boiler  room  were  completely  destroyed 
or  filled  with  steam  and  smoke. 

The  steam  contained  in  the  boiler  connected  to  the  fire  pump 
would  be  its  "store"  to  draw  from,  assuming  that  it  would  then 
be  impossible  to  feed  more  water  or  coal  to  the  boiler.  This 
supply,  however,  would  run  the  fire  pumps  for  a  long  period,  and 
unless  some  such  provision  were  made,  the  fire  service  would  end 
with  the  first  damage  to  the  piping.  It  is  no  uncommon  thing 
to  find  a  fire  pump  placed  in  the  basement  or  back  of  the  boilers 
and  in  other  locations  that  would  compel  the  operator  to  leave 
the  pump  to  itself  as  soon  as  a  little  steam  or  smoke  reached  him. 

If  the  outside  risk  is  great,  the  fire-pump  service  should  be 
guarded  in  every  possible  way.  The  insurance  companies  demand  a 
specific  construction,  but,  their  rules  being  general,  expert  judgment 
is  not  always  used  for  each  individual  risk.  Their  rules  oftentimes 
demand  things  wholly  useless  in  some  cases,  and  in  others  neglect 
to  make  demands  that  are  absolutely  essential  for  protection 
against  fire.  This  is  a  feature  of  their  business  that  cannot  well 
be  otherwise. 

The  fire  protection  and  fire  fighting  arrangements  demanded  by 
the  insurance  companies  are  as  good  as  can  be  stated  for  general 
use,  but  the  engineer  must  locate  the  unprotected  risks  about  his 
plant  and  make  the  necessary  provisions  against  fire.  The  fact  that 
the  plant  is  equipped  so  that  it  can  collect  its  insurance  is  of  but 
little  or  no  value,  for  it  encourages  a  feeling  of  indifference  to  fire, 
and  though  a  dollar  of  insurance  may  be  collected,  possibly  ten 


FIRE   SERVICE   PIPING. 


373 


would  be  lost  indirectly  on  account  of  the  fire.  The  fire  and  low 
pressure  service  in  a  power  house  can  both  be  supplied  from  the 
fire  pump,  but  they  should  be  separate  lines,  with  a  valve  at  the 
fire  pump  to  shut  off  all  indoor  piping.  The  low-pressure  main 
would  ordinarily  be  a  separate  line,  the  other  low-pressure  lines 
being  supplied  from  the  fire  main  with  an  outside  valve.  If  it  is 
necessary  to  open  certain  valves  and  close  others  in  case  of  fire 
some  established  system  should  be  followed,  such  as  yellow  valves 
closed  and  red  valves  opened  in  case  of  fire.  These  valves  should 
lie  as  close  in  a  group  as  possible,  and  a  chart  should  be  hung  up 
near  them,  showing  all  the  valves  to  be  operated,  as  it  is  quite 
easy  for  any  operator  to  forget  when  he  becomes  excited.  If  there 


tz 


HOVS£. 


SHOP 


* 

JHOP 

\ 

\ 
\ 

Jt 

^  ^9 

If     J/VD/CffTV/tJk  KffWflfl/VTJ 

)^-----^-.-^_--^^^ 

FIG.  295  (Mi-3>. 


F 


••aa-ris  s^^f' 


are  indoor  fire  taps  at  other  buildings  they  may  be  supplied  from 
the  fire  main,  with  the  valves  left  open  until  the  line  becomes 
damaged  or  the  men  are  driven  from  the  interior  of  the  building. 
This  layout  is  shown  in  Fig.  295  (Mi~3.)  No.  i  shows  the  fire 
pump,  No.  2  the  auxiliary  or  reserve  pump,  and  No.  3  the  boiler 
feed  pump. 

The  fire  main  is  in  the  form  of  a  loop,  thus  permitting  any 
portion  to  be  shut  off  and  still  have  fire  protection.  The  valves,  B, 
are  the  shut-off  valves  and  do  not  require  indicator  posts,  as  they 
should  not  be  operated  in  case  of  fire.  The  valves,  C,  shut  off 
water  from  the  inside  of  shop  buildings,  and  these  should  be  fitted 
with  indicator  posts.  The  fire  hydrants  are  indicated  by  the 
letter  Z>.  If  the  lines  running  into  the  shops,  shown  with  the  shut- 
off  valve,  C,  are  used  for  plumbing  fixtures  only,  it  would  be 
advisable  to  supply  them  from  the  separate  main  indicated  at  A, 


374  STEAM  POWER   PLANT  PIPING  SYSTEMS. 

so  that  they  would  be  shut  off  before  running  the  fire  mains  under 
high  pressure.  By  thus  arranging  the  piping  there  would  be  no 
valves,  C,  to  handle,  the  only  valves  to  be  opened  or  closed  being 
at  the  fire  pump. 

The  main,  A,  could  have  a  reducing  valve  fitted  in  it  so  that 
it  would  always  be  full  open  when  the  fire  pump  was  working  on 
low  pressure  and  closed  whenever  the  fire  lines  are  operated  under 
high  pressure.  This  arrangement  would  protect  the  low  pressure 
line  and  simplify  the  operation  of  the  system  in  case  of  fire,  as 
practically  the  only  operation  necessary  would  be  to  increase  the 
water  pressure  by  changing  the  position  of  the  weight  on  the  pump 
governor.  An  automatic  device  can  be  used  for  shifting  the 
weight  on  the  governor  and  shut  off  the  low-pressure  service.  This 
can  be  done  by  a  loosely  fitting  piston  in  the  fire  service  discharge, 
which  would  operate  the  valve  and  shift  the  position  of  the  weight 
previously  mentioned,  the  operating  piston  leaving  the  discharge 
from  the  fire  pump  unobstructed  while  the  fire  pump  was  oper- 
ating under  high  pressure.  With  this^  device  it  is  possible  to 
attach  a  hose  to  any  hydrant  under  20  Ib.  pressure,  and  by  the 
time  the  hydrant  valve  is  opened  there  will  be  125  Ib.  pressure 
on  the  entire  fire  system,  and  the  low-pressure  system  will  be 
shut  off.  The  fact  that  the  speed  of  the  fire  pump  had  increased 
and  the  pressure  raised  would  be  the  first  indication  to  the  station 
operator  that  the  fire  service  was  being  used. 

With  this  device  in  operation  the  fire  line  could  not  be  used 
for  any  other  service,  as  the  flow  in  the  pipe  line  would  trip  the 
valve.  The  construction  of  such  an  automatic  valve  is  shown 
in  Fig.  296  (Mi-4).  The  piston  fits  the  body  of  this  special  valve 
so  closely  that  the  flow  of  water  to  one  hose  is  sufficient  to  trip  the 
weighted  lever  and  draw  out  the  countenveight  on  the  pump 
governor.  The  special  valve  is  illustrated,  showing  the  low- 
pressure  main  shut-off  and  the  piston  out  of  the  flow  of  the 
water.  The  final  travel  of  the  piston  is  given  to  it  by  the  weighted 
lever.  To  place  the  pump  on  low  pressure  after  it  has  been  used 
for  fire  service,  the  lever  is  returned  to  its  former  position.  This 
returns  the  piston  to  its  original  position  and  shifts  the  counter- 
weight on  the  pump  governor,  so  that  the  diaphragm  does  not 
have  to  raise  so  great  a  weight  in  closing  the  balanced  steam  valve. 

It  will  be  noted  that  normally  the  lever  is  nearly  in  a  vertical 
position,  thus  requiring  but  little  pressure  under  the  piston  to  tip 


FIRE   SERVICE   PIPING. 


375 


it  over.  If  all  the  piping  is  tight  and  the  piston  fits  its  bore  closely, 
this  pressure  controller  can  be  used  in  connection  with  the  auto- 
matic sprinklers.  The  standard  underwriter  pump  has  a  water 
relief  valve  at  D,  and  this  should  be  provided  in  all  cases  where 
the  pump  is  to  be  used  for  fire  service.  Priming  pipes  and  a 
hand-operated  cylinder  oil  pump  should  be  fitted  to  the  pump. 
All  makes  of  underwriters'  fire  pumps  are  designed  to  conform 


FIG.  296  (Mi-4). 

to  the  same  specification,  but  there  are  so  many  details  pertaining  to 
pump  construction  not  mentioned  in  the  underwriters'  specifica- 
tions that  no  two  makes  of  pumps  can  be  considered  equal. 

Possibly  no  other  feature  in  the  design  of  a  pump  governs 
its  value  so  much  as  its  weight.  Though  metal  can  be  waste- 
fully  used  in  the  design  of  a  pump,  it  is  quite  unlikely  that  a 
manufacturer  would  add  weight  needlessly.  Strength  and  large 
port  openings,  liberal  wearing  surfaces,  etc.,  are  secured  only  by 
increased  weight,  and  it  is  quite  impossible  to  design  a  light  pump 
having  the  same  merits  as  a  heavier  one.  When  securing  prices, 
the  weights  of  the  pumps  should  be  compared. 

Referring  to  Fig.  295  it  will  be  seen  that  water  is  supplied  to 
each  hydrant  from  both  directions,  that  is,  each  side  of  the  loop 


376  STEAM  POWER   PLANT  PIPING   SYSTEMS. 

is  supplying  water  to  those  hydrants  being  used.  A  system 
designed  in  this  manner  supplied  from  a  pump  with  an  8-in.  dis- 
charge would  require  loop  piping  of  6-in.  pipe.  The  loop  system 
is  practically  equivalent  to  running  a  double  pipe  line  of  this  size 
to  each  hydrant.  The  lineal  feet  of  pipe  in  the  loop  main  is  but 
slightly  greater  than  in  a  single  main  system,  and  the  area  of  the 
pipe  can  be  reduced  to  just  one-half  that  of  a  single  main.  Not 
only  is  a  more  reliable  system  secured  in  this  manner,  but  also 
one  which  is  no  more  expensive  to  install.  The  fire  main  should 
be  placed  at  the  same  depth  as  the  city  water  pipe  in  the  same  lo- 
cality, thus  avoiding  the  possibility  of  freezing. 

For  buildings  of  ordinary  height  the  hydrants  should  be  placed 
at  a  distance  from  a  building  equal  to  its  height.  This  avoids  the 
possibility  of  the  walls  falling  on  the  hydrants  or  the  firemen. 
Hydrants  or  indicator  valves  posts  placed  too  close  to  a  wall  are 
liable  to  become  unapproachable  in  case  of  fire,  and  cause  a  serious 
loss  of  pressure  and  a  waste  of  water. 

Fire  protection  for  power  stations,  shops,  etc.,  can  be  divided 
into  two  separate  classes:  interior  and  exterior  service.  The 
conditions  encountered  in  each  case  should  be  thoroughly  studied 
and  understood  before  attempting  to  design  either  service.  The 
interior  service  is  the  proverbial "  stitch  in  time  "  which "  saves  nine." 
It  is  the  quick  use  of  water  in  small  quantities  applied  to  a  fire 
at  its  beginning  that  makes  the  well-provided  interior  protection 
so  valuable.  A  room  50  by  100  ft.  may  have  only  two  ij-inch 
hose  reels  on  the  wall,  but  if  they  can  be  put  into  use  without  delay 
and  are  so  located  that  they  can  be  readily  reached  and  will  cover 
the  entire  room,  there  will  be  but  little  chance  of  a  fire  getting 
beyond  the  control  of  the  interior  fire  protection. 

A  study  of  the  necessities  in  fire  fighting,  by  those  who  make  this 
their  sole  occupation,  are:  First,  a  system  of  water  supply  ade- 
quately covering  the  territory  to  be  protected.  Second,  an  alarm 
system  covering  the  territory  to  be  protected.  Third,  an  organ- 
ization of  men  who  have  been  trained  and  understand  their  duty 
in  case  of  fire.  Fourth,  apparatus  for  pumping  water  to  the  highest 
and  most  remote  parts  of  a  building.  Fifth,  means  of  egress  when 
the  building  is  no  longer  tenable.  Sixth,  auxiliary  apparatus  for 
extinguishing  smaller  fires  without  using  large  quantities  of  water, 
and  thus  causing  serious  losses  through  damage  by  water. 

A  point  which  requires  the  most  careful  consideration  is  the 


FIRE  SERVICE  PIPING. 


377 


selection  of  fire  hose,  a  subject  which  has  caused  the  city  fire  depart- 
ments unlimited  trouble.  Any  article  containing  rubber  depre- 
ciates with  age,  and  still  rubber  is  essential  in  the  manufacture  of 
water-tight  hose.  It  certainly  seems  wasteful  to  buy  high-grade 
hose  and  allow  it  to  lie  until  it  is  useless,  but  there  is  no  method  of 
avoiding  this.  It  has  in  many  instances  been  the  unfortunate 
experience  of  fire  departments  that  it  is  impossible  to  put  out  fires 
with  old  weak  hose.  Fire  departments  cannot  afford  to  take 
chances  with  old  hose  past  its  useful  life,  and  companies  and 
individuals  cannot  better  afford  to  take  such  chances.  The  hose 
question  is  too  often  entirely  or  seriously  neglected,  although  it  is 


FIG.  297  (Mi-s). 

one  of  the  most  important  parts  of  fire  protection  system,  as 
firemen  can  do  nothing  with  rotten  hose.  Insurance  companies 
realize  this  point  and  for  this  reason  recommend  tanks  and  pails, 
and  preferable  to  all  other  methods,  a  regular  piped  sprinkler 
system,  as  they  know  that  the  hose  is  frequently  unfit  for  use 
when  it  is  required,  or  the  men  are  not  at  hand  to  use  it. 

Alarm  systems  receive  little  or  no  attention,  fires  usually  being 
first  reported  when  some  one  discovers  smoke  or  flames  coming 
from  a  window  and  reports  it  to  the  engineer.  Buildings  should 
be  fitted  with  a  fire  alarm  in  each  room.  This  can  be  accomplished 
in  a  very  simple  manner,  as  shown  in  Fig.  297  (Mi~5).  The 
alarm  consists  essentially  of  two  wires  twisted  together  and  insulated 
from  each  other  by  a  compound  which  melts  at  a  comparatively 
low  temperature.  These  twisted  wires  are  run  under  benches, 
around  walls,  along  the  ceiling,  at  stairways  and  any  other  exposed 
point.  The  number  of  circuits  which  can  be  thus  connected  is 
unlimited.  There  can  be  any  number  of  circuits  in  a  room,  each 


3/8  STEAM   POWER   PLANT  PIPING  SYSTEMS. 

having  a  marker  at  B,  which  becomes  discolored  as  soon  as  the 
circuit  is  completed  and  rings  the  bell,  C,  in  that  particular  room, 
and  also  operates  the  light  or  annunciator  and  sends  in  an  alarm 
to  the  fire  station.  The  batteries  may  be  placed  at  E  and  the 
entire  system  operated  on  low  voltage.  The  lamps  or  the  volt- 
meter, F,  show  the  voltage  of  the  batteries  at  all  times.  The  fire- 
man (or  the  engineer,  if  he  is  in  charge  of  the  fire  system)  then 
sees  where  the  wires  A  have  been  heated,  and  if  the  location  is  not 
easily  found  he  can  look  at  the  markers,  B,  to  locate  the  short- 
circuit,  and,  if  caused  by  an  accident,  it  can  easily  be  repaired  by 
rewaxing.  This  device  has  the  advantage  that  it  can  be  set  low 
down  and  in  dangerous  locations  without  the  dangers  accompany- 
ing the  use  of  automatic  sprinklers.  This  device  would  set  off 
the  alarm  before  the  sprinklers  would  have  time  to  work,  and  fire- 
men would  be  on  hand  long  before  the  fire  had  gained  much  head- 
way. The  wires  would  be  quite  small  and  the  cost  of  the  installa- 
tion would  be  very  slight,  as  it  could  easily  be  installed  by  the 
resident  electrician  or  one  of  the  engineers.  Instead  of  running 
separate  positive  and  negative  leads,  double  conductor  wire  could 
be  used,  the  wires  being  separated  where  the  twisted  wires  are 
attached. 

The  inside  fire  service  should  be  a  branch  from  the  fire  main,  as 
shown  in  Fig.  295,  with  an  indicator  valve,  C,  for  each  building,  as 
it  is  desirable  that  the  inside  fire  service  be  used  in  each  building 
until  it  is  no  longer  tenable.  The  main  shown  at  A  would  be 
used  to  supply  all  services  other  than  the  fire  service. 

With  such  an  alarm  system  and  the  pump  pressure  device  shown 
in  Fig.  296,  it  would  be  good  practice  to  give  an  alarm  whenever 
both  are  caused  to  operate  together,  showing  that  heat  has  made 
the  wires,  A,  come  in  contact,  and  that  water  is  being  drawn  from 
the  fire  system.  In  each  room  at  the  alarm,  C,  there  should  be  a 
spring-closed  switch,  which  should  be  opened  or  closed,  giving  an 
alarm  for  the  city  fire  department  or  for  additional  help,  without 
necessitating  leaving  the  room  where  the  fire  is  found.  This 
general  fire  system,  if  arranged  in  similar  manner  to  that  of  the  city 
fire  department  and  adaptable  to  private  institutions,  would  be 
installed  as  follows: 

1.  Fire  mains  installed  on  the  loop  plan  as  shown  in  Fig.  295. 

2.  Fire  pumps  installed  and  isolated  with  door  and  windows 
opening  outside. 


Pi  RE  SERVICE   PIPING.  379 

3.  Fire  pumps  having  an  individual  indestructible  steam  line 
from  not  less  than  two  boilers. 

4.  Fire  pump  having  pressure  raising  device,  shown  in  Fig.  296. 

5.  Fire  lines  to  individual  buildings  with  valve  at  C,  as  shown 
in  Fig.  295. 

6.  Hose  provided  for  all  rooms  and  connected  ready  for  instan- 
taneous use. 

7.  Hose  tested  at  regular  intervals. 

8.  Alarm  system  as  shown  in  Fig.  297. 

9.  Employees  drilled  at  least  once  a  month. 

10.  Chemical  extinguishers  in  locations  where  water  would 
cause  considerable  damage,  but  hose  also  installed  in  these  locations. 

11.  Fire  escapes  placed  so  that  a  man  with  a  fire  hose  can 
remain  the  longest  possible  time  and  know  that  he  can  get  out. 

12.  Standpipes  extending  to  the  roofs  of  all  buildings. 

Class  M2  —  Fire  Service  to  Hydrants.  The  hydrants,  D,  shown 
in  Fig.  295  would  ordinarily  have  two  openings  for  2^-in.  hose,  and 
have  an  inlet  not  smaller  than  the  size  of  the  main.  In  deter- 
mining the  depth  to  bury  the  fire  main,  the  length  of  the  hydrant 
that  will  be  used  should  be  known.  The  standard  depth  is  5  ft. 
from  the  pavement  to  the  bottom  of  the  pipes.  In  placing  the 
hydrant  a  flat  stone  well  rammed  down  should  be  put  under  it  to 
prevent  settling.  Old  bricks,  stone,  etc.,  should  be  placed  around 
the  drain  hole  to  permit  the  water  to  seep  away  and  also  to  prevent 
sand  and  gravel  from  entering  the  hydrant.  The  hose  connection 
should  point  toward  the  building. 

Standard  hydrants  require  a  special  wrench  to  open  the  valve, 
and  as  these  wrenches  are  also  necessary  to  remove  the  hose  caps 
and  also  to  attach  the  hose,  little  would  be  gained  by  having  a 
handwheel  fixed  to  the  hydrant,  even  though  it  were  in  a  position 
where  it  would  not  be  tampered  with.  In  some  installations  the 
hose  and  fire  tools  are  kept  in  a  house  surrounding  the  hydrant. 
A  better  plan,  however,  is  to  have  a  central  fire  station  where  all 
hose  for  the  hydrants  is  kept,  and  have  hose  carts  to  carry  it. 
By  having  a  central  station  it  serves  as  a  meeting  point  in  case  of 
fire,  and  the  chief  has  therefore  better  control  of  the  men. 

A  convenient  form  of  cart  is  shown  in  Fig.  298  (M2-i).  Each 
5o-ft.  length  of  hose  should  be  laid  in  the  top  of  the  cart  and  the 
lower  shelf  used  for  tools,  etc.  For  use  around  power  stations  and 
shops  it  is  quite  inconvenient  to  have  all  the  hose  on  one  reel. 


380 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


The  house  in  which  the  cart  is  kept  should  have  a  glass-closed 
opening  over  a  spring  lock,  with  a  notice  above  the  glass:  "In 
case  of  fire  break  glass  and  unlock  the  door."  Another  method 
is  to  have  a  sliding  bolt  lock  with  a  conspicuous  sign:  " Slide  this 
bolt  to  open  door  and  give  alarm,"  there  being  another  door 
which  could  be  used  without  setting  off  the  alarm.  In  many 
respects  the  latter  form  is  preferable,  as  there  is  less  liability  of 
its  being  molested.  It  also  would  bring  additional  help  more 
readily. 


FIG.  298  (M2-i). 


FIG.  299  (M3-i). 


Class  M3  —  Fire  Service  to  Interior  Connections.  A  branch  of 
the  fire  main  with  its  indicator  post  is  shown  in  Fig.  295.  The 
indicator  simply  consists  of  a  slide  showing  a  sign,  "Open"  or 
"Closed,"  according  to  the  position  of  the  valve.  Indicator 
posts  avoid  uncertainty  and  confusion,  as  few  men  can  tell  by  the 
movement  of  a  valve  wheel  whether  it  is  open  or  closed.  In  case 
of  fire  the  few  who  know  would  probably  become  confused  and 
think  a  valve  was  open  when  in  reality  it  was  closed.  If  an 
indicator  post  must  necessarily  be  placed  close  to  the  building  it 
should  be  located  at  one  of  the  corners,  so  that  it  could  be  operated 
from  either  side,  permitting  the  operator  to  avoid  the  heat  and 
smoke. 

The  interior  fire  lines  should  be  supported  on  brick  walls  or  in 
such  a  manner  that  they  will  remain  serviceable  for  the  longest 
possible  period.  The  placing  of  the  hose  reels  should  receive 
the  most  careful  consideration,  since  much  depends  upon  where 
a  man  is  located  when  using  the  hose,  and  to  what  extent  the  hose 
is  exposed  to  danger.  Fig.  299  (M3~i)  shows  the  plan  of  a  large 
room  with  one  outside  wall. 

The  hose  shown  by  the  dotted  line,  A,  is  connected  to  a  reel 


FIRE  SERVICE  PIPING.  381 

mounted  on  the  inside  division  wall.  Although  all  the  objection- 
able features  of  such  an  arrangement  are  evident  there  are  prob- 
ably more  hose  reels  installed  in  this  manner  than  in  any  other. 
The  possible  reason  for  this  is  that  the  designers  wish  to  keep  all 
the  hose  and  pipe  lines  near  the  center  of  the  building  to  protect 
them  from  freezing.  The  economy  of  such  an  arrangement  is 
extremely  doubtful,  as  the  efficiency  of  the  fire  service  is  greatly 
reduced. 

If  a  fire  were  discovered  in  a  room  having  the  reel  and  hose 
attached  as  at  A,  in  Fig.- 299,  it  would  be  necessary  to  pass  through 
the  greater  part  of  the  room  to  get  at  the  hose,  and  there  would  be 
danger  of  the  man  taking  down  the  hose  and  trying  to  put  out 
the  fire  being  blinded  and  overcome  by  the  smoke.  Even  though 
the  operator  had  the  hose  down  from  the  reel  and  nozzle  as  at  J5, 
there  would  be  serious  danger  of  being  overcome  by  smoke  long 
before  the  fire  had  done  any  serious  damage.  There  is  in  reality 
only  one  correct  position  for  a  hose  reel  or  rack,  and  that  is  close 
to  windows  where  air  can  be  obtained,  and  where  safe  exit  is 
possible.  This  permits  a  man  to  get  to  the  hose  in  case  a  fire  has 
made  considerable  headway.  He  can  also  protect  his  hose  from 
the  fire  as  long  as  he  is  able  to  use  it.  The  fire  escape  shown 
permits  the  hose  C  to  be  used  in  the  next  room  by  running  the  line 
out  of  the  window  and  across  the  fire  escape. 

It  is  quite  common  practice  to  place  hose  racks  in  hallways  back 
of  the  workrooms  as  shown  at  Z>,  and  expect  men  to  work 
from  the  center  of  the  building.  It  may  be  an  ideal  place  from 
which  to  suppress  a  fire,  but  in  laying  out  fire  systems  the  safety 
of  the  fire  fighters  should  receive  the  first  consideration,  and  the 
fire  service  should  be  designed  to  insure  their  safety,  otherwise 
the  money  invested  in  fire  protection  will  be  useless  for  want  of 
men  to  use  it.  There  are  many  designs  of  hose  racks,  reels,  valves, 
etc.,  used.  The  following  conditions  should  be  fulfilled  by  satis- 
factory hose  racks  and  reels,  but  they  are  difficult  to  combine  in 
one  device. 

1.  The  device  must  permit  the  hose  to  be  quickly  and  easily 
removed. 

2.  Leakage  past  the  hose  valve  must  not  be  discharged  into 
the  hose,  causing  it  to  be  injured. 

3.  The  hose  should  not  lie  with  short-radius  bends  in  it,  as 
the  material  of  which  hose  is  made  will  in  time  assume  the  forms 


3$2  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

in  which  it  has  been  held  for  any  length  of  time  and  is  easily 
broken  when  straightened  out. 

4.  The  hose  should  lie  so  that  it  will  drain  itself. 

5.  The  hose  should  be  inclosed  where  oil  is  extensively  used. 
These  conditions  are  quite  exacting,  and  the  nearest  approach 

to  them  is  shown  in  Fig.  300  (M3-2).  This  arrangement  consists 
of  a  shelf  or  shelves  each  large  enough  to  hold  fifty  ft.  of  hose  laid 
straight,  one  or  more  lengths  on  a  shelf  and  the  hose  supported 


FIG.  300  (M/3-2). 

preferably  in  a  U-shaped  trough.  The  hose  is  detached  from  the 
hose  valve,  and  the  supports  are  pitched  to  permit  water  to  drain 
from  the  hose.  To  further  protect  the  hose  there  should  be  a 
sectional  drop  door  protecting  the  shelves  from  the  circulation  of 
air.  This  is  an  ideal  support,  and  like  most  ideal  arrangements, 
as  a  rule,  it  does  not  fit  into  the  place  where  it  is  wanted. 

One  of  the  most  practical  forms  of  hose  support  is  that  shown 
in  Fig.  301  (M3~3).  This  form  of  hose  reel  can  be  used  in  almost 
any  location.  As  shown  by  the  illustration,  it  is  placed  in  a  vertical 
position,  the  hose  being  wound  in  the  form  of  a  spiral,  the  nozzle 
being  at  the  top.  The  hose  is  supported  over  its  entire  length. 
The  shortest  curve  in  the  hose  is  that  of  the  drum.  The  hose  is 
attached  to  the  swivel  joint.  A  check  valve  is  placed  at  A,  which 
remains  open  as  long  as  there  is  no  water  passing  through  the 
valve  B.  Water  which  may  be  in  the  hose,  or  which  leaks  past 
the  valve  B,  would  be  discharged  through  this  open  check  valve. 
If  the  hose  is  kept  in  a  room  where  oil  is  extensively  used,  a  sheet 
of  heavy  wrapping  paper  may  be  put  around  the  outside  to  protect 
the  hose.  This  can  readily  be  torn  away  when  the  hose  is  required. 

The  form  of  support  shown  in  Fig.  301  ^3-3)  has  all  the 
desirable  features  except  that  the  hose  is  held  in  a  curved  position. 
The  radius  of  the  drum  is,  however,  so  great  compared  with  that 
of  other  supports  used,  that  the  injury  resulting  from  this  curvature 
must  be  very  slight.  The  hose  may  be  permanently  attached  to  the 
service  line  in  the  arrangement  of  Fig.  299  and  nearly  all  other 
forms,  provided  a  check  valve  is  fitted,  as  shown  at  A  in  Fig.  301. 


FIRE   SERVICE   PIPING. 


383 


NOZZLl  flT 


There  are  hose  reels  in  use  with  a  central  water  connection  as  shown 
in  Fig.  301,  the  drum,  however,  revolving  on  a  horizontal  axis. 

Such  an  arrangement  is  open  to  the  same  objections  as  the  style 
of  hose  support  shown  in  Fig.  302  (^£3-4).  The  entire  weight  of 
the  hose  is  carried  on  only  a  portion  of  its  length,  and  the  weight 
of  the  hose  thus  tends  to  flatten  it.  If 
there  is  any  water  in  the  hose  in  such 
forms  it  drains  to  the  lower  loops  and  re- 
mains there,  this  being  the  difficulty  in 
practically  all  forms  of  hose  support.  It  is 
a  very  difficult  detail  to  remedy.  Another 
form  of  hose  support  is  shown  in  Fig.  303 
(M3~5).  This  support  is  objectionable 
on  account  of  the  sharp  bends  necessary 
in  piling  the  hose  and  the  weight  resting 
on  the  bottom  layers  tending 
to  flatten  them.  Further  there 
is  no  method  of  draining  a 
hose  piled  in  this  manner,  and 
in  this  respect  it  is  even  worse 
than  that  shown  in  Fig.  302. 
This  form  of  hose  support  is 
very  largely  used,  and  the  only 
excuse  for  it  is  that  it  is  cheap 
and  can  be  folded  back 
against  the  wall  and  thus 
space.  The  form  of  support 
(M3~6)  could  be  made  quite 
avoid  the  sharp  bend  in  the 


FIG.  301  (M3-3). 


FIG.  302 
(M3-4). 


occupies   very   little 

shown    in    Fig.   304 

cheaply    and    would 

hose,  would  drain  properly,  and  is  supported  throughout  its  entire 

length. 

Class  M4  —  Fire  Service  on  Roof.  Though  this  class  of  fire 
protection  is  very  efficient,  it  is  generally  neglected.  A  power 
house,  with  the  exception  of  the  roof,  is  quite  easily  constructed  in 
a  fireproof  manner.  This  is  equally  true  of  many  shops.  If  a 
power  plant  is  located  where  it  is  in  danger  from  surrounding 
buildings,  it  may  be  advisable  to  use  the  roof-wetting  pipes  shown 
in  Fig.  294.  But  ordinarily  a  hose  and  standpipe  at  each  end  of 
the  building  are  sufficient. 

A  very  efficient  manner  in  which  to  install  a  roof  standpipe  is 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


shown  in  Fig.  305  (M4~i).  The  hose  and  valve  are  on  a  shelf  or 
rack  on  the  inside  of  the  building,  the  heat  of  the  room  preventing 
the  water  pipe  and  parts  from  freezing.  The  cast-iron  doors  and 
frames  are  built  in  the  wall,  and  the  doors  open  out  on  to  a  plat- 
form, which  is  set  sufficiently  low  so  that  a  man  will  be  protected 


FIG.  303  (M3-s). 


FIG.  304  (M3-6). 


somewhat  from  the  heat  of  the  fire.  The  ladder  which  reaches 
this  platform  and  is  continued  on  and  over  the  wall  to  the  roof 
permits  easy  access  to  the  hose  and  the  roof. 

Men  working  on  top  of  a  burning  roof  would  soon  leave  it  rather 
than  run  the  risk  of  being  dropped  into  the  burning  building 


FIG.  305  (M4-i). 

because  of  the  roof  sheathing  giving  way  or  the  trusses  buckling. 
The  most  secure  point  at  which  to  locate  the  platform  shown  in 
Fig-  3°5  is  at  tne  outside  end  of  the  power  plant  and  at  a  division 
wall,  as  is  shown  by  the  dotted  lines.  This  location  gives  a  better 
range  of  both  the  boiler  and  engine  room  roof,  and  is  the  safest 
position  along  the  end  wall,  as  it  is  braced  by  the  division  wall. 


FIRE  SERVICE  PIPING.  385 

Another  method  of  supplying  water  to  the  roof  is  by  means  of  an 
outdoor  standpipe,  ladder  and  platform,  as  shown  in  Fig.  305,  but 
without  the  hose  and  the  hose  valve  located  inside  the  wall.  The 
standpipe  in  this  case  would  have  an  underground  connection 
and  a  valve  fitted  with  a  drain  which  could  be  opened  when  the  line 
is  shut  off.  Such  a  line  would  be  fitted  with  an  indicator  post. 
With  the  latter  arrangement  it  would  be  necessary  to  carry  a  hose 
up  the  ladder  whenever  it  was  needed. 

The  outdoor  standpipe  would  ordinarily  be  placed  alongside  the 
fire  escape  if  used  for  factory  protection,  and  there  would  be  one 
or  two  hose  connections  with  valves  at  each  floor,  and  possibly  two 
hose  connections  at  the  roof.  This  standpipe  would  be  made  of 
large  diameter,  as  all  water  used  for  fire  protection  might  be  taken 
from  this  pipe.  For  power  plant  protection  the  system  shown  in 
Fig.  305  can  more  easily  and  quickly  be  put  into  service,  and  it  is 
also  somewhat  cheaper  to  install.  In  attempting  to  economize, 
however,  the  utility  and  reliability  of  operation  must  not  be  over- 
looked, as  the  value  of  fire  protection  depends  largely  upon  what 
provisions  have  been  made  to  prevent  serious  loss  of  pressure  in 
case  the  interior  pipe  lines  should  be  broken,  as  may  happen  in  the 
system  shown  in  Fig.  305.  There  should  be  some  means  provided 
to  permit  shutting  off  all  pipe  lines  which  may  be  accidentally 
broken,  and  it  should  further  be  provided  that  all  such  lines  can 
be  shut  off  from  the  exterior  of  the  building,  even  though  the  walls 
of  the  building  have  fallen.  If  such  means  cannot  be  provided 
for,  the  arrangement  in  Fig.  305,  an  outside  standpipe  with  an 
underground  valve  located  some  distance  from  the  building, 
should  be  used. 

Class  M5  —  Fire  Service  from  the  City  Supply.  The  extent 
to  which  city  pressure  can  be  applied  in  fire  protection  depends 
upon  the  available  pressure  and  the  extent  of  the  fire  protection 
intended  by  the  system.  In  the  larger  cities  comparatively  low 
pressure  is  maintained,  and  the  necessary  pressure  for  fire  service 
is  obtained  by  means  of  a  fire  engine  or  pumps.  Smaller  cities 
and  towns  resort  to  a  system  of  fire  alarm  and  increase  the  pressure 
on  the  main  during  times  of  fire.  This  increase  of  pressure  is 
generally  quite  small  compared  with  that  obtainable  from  fire 
pumps,  a  pressure  of  150  Ib.  per  sq.  in.  being  quite  general 
in  the  latter.  The  usual  pressure  in  towns  is  20  Ib.  per  sq.  in., 
and  this  is  seldom  increased  above  60  Ib.  The  plumbing 


386  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

and  water  lines  would   be   strained  if  a   higher  pressure  were 
carried. 

If  a  pressure  of  60  Ib.  is  quickly  available  on  the  city  water 
system,  there  would  "be  no  real  necessity  for  an  independent  fire 
pump,  provided  the  building  were  not  more  than  30  ft.  high  or 
about  50  ft.  wide.  A  pressure  of  60  Ib.  at  the  hydrant  will  give  a 
discharge  of  about  122  gal.  per  min.  through  a  o.75-in.  nozzle 
at  the  end  of  a  loo-ft.  2.5  inch  hose  line.  The  stream  of  water 
will  rise  vertically  to  a  height  of  about  70  ft.  and  reach  horizontally 
to  a  distance  of  about  50  ft.  under  these  conditions.  A  ij-in. 
nozzle  will  deliver  about  twice  the  amount  of  water  that  a  0.7  5 -in. 
nozzle  will  deliver,  and,  though  it  will  not  project  it  to  the  same 
height,  it  will  project  it  a  greater  horizontal  distance. 

Plants  located  within  the  district  of  fire  engine  service  should 
have  their  own  inside  fire  service,  and  for  this  purpose  the  city 
pressure  would  in  most  cases  be  sufficient,  as  the  height  and  general 
dimensions  of  the  rooms  would  not  be  too  great  to  permit  water 
to  be  delivered  to  any  part  of  the  room.  If  the  building  is  high 
it  will  be  necessary  to  place  a  tank  on  the  roof,  using  an  ordinary 
house  pump  to  fill  the  tank  if  the  city  pressure  is  not  sufficient  to 
deliver  the  water  to  that  height. 

Class  M6  —  Fire  Service  to  Low-Pressure  Service.  If  a  fire 
pump  were  connected  to  the  fire  mains  only,  it  would  require 
special  attention  to  keep  it  in  working  order,  so  that  it  might  be 
used  at  any  moment.  Should  the  plant  and  its  surrounding  build- 
ings require  water  at  low  pressure  and  the  plant  have  its  own 
water  supply,  it  will  be  a  good  plan  to  use  the  fire  pump  for  this 
service.  By  using  the  fire  pump  for  the  low-pressure  service  it  is 
kept  in  constant  use  and  its  condition  is  thus  known  at  all  times. 

The  low-pressure  service  should  be  connected  to  the  fire  mains 
or  pump  discharge  in  such  a  manner  that  it  can  be  shut  off  quickly 
in  case  of  fire,  the  means  for  shutting  off  the  pump  being  so 
arranged  that  the  pump  can  be  turned  off  outside  of  the  building 
which  is  to  be  protected.  Ordinarily,  the  best  arrangement 
would  be  to  start  the  low-pressure  piping  system  at  the  fire  pump 
discharge,  a  valve  being  inserted  in  the  line  so  that  the  latter  could 
be  cut  off.  By  taking  all  the  general  service  connections  from  this 
main,  only  one  main  would  have  to  be  shut  off  in  case  of  fire. 

This  one  valve  would  shut  off  the  water  service  from  all  plumbing 
fixtures,  wash  water  for  the  car  barns,  and  the  water  service  to 


FIRE   SERVICE   PIPING.  387 

the  journals,  etc.,  and  in  many  cases  also  the  water  to  the  open 
heaters.  In  most  instances  no  serious  result  or  inconvenience 
would  be  experienced  if  such  services  were  shut  off  during  a  fire, 
but  if  it  is  absolutely  essential  to  maintain  some  portion  of  the 
low-pressure  water  service  it  would  be  advisable  to  run  a  separate 
main  from  the  fire  pump  discharge,  the  latter  line  then  being 
fitted  with  a  reducing  valve.  The  main  line,  however,  should  be 
arranged  so  that  it  can  be  shut  off,  since  there  will  be  many  minor 
connections  taken  from  it  which  might  be  broken  in  case  of  fire, 
and  thus  cause  a  loss  of  pressure  and  a  waste  of  water. 

If  three  pumps,  a  feed  pump,  fire  pump  and  reserve  pump, 
are  employed,  the  reserve  pump  can  be  used  to  supply  the  low- 
pressure  service.  The  principal  point  to  consider  is  how  to  reduce 
to  a  minimum  the  amount  of  water  used  for  purposes  other  than 
fire.  The  use  of  a  reducing  valve  in  a  branch  from  the  fire  line 
is  liable  to  cause  trouble  if  the  low-pressure  pipe  is  damaged  and 
considerable  water  would  then  be  lost,  even  though  the  pressure 
were  reduced. 

A  positive  and  safe  method  is  to  shut  off  all  the  lines  to  the  low- 
pressure  service  by  gate  valves,  as  previously  mentioned,  and  if 
necessary  permit  the  feed  pump  to  supply  the  boilers  with  cold 
water  in  times  of  fire.  If  an  overhead  tank  is  installed  it  can  be 
used  to  supply  water  for  the  engine  journals  or  as  much  of  the  low 
pressure  system  as  is  unlikely  to  be  injured  by  fire. 

Class  M7  —  Fire  Service  to  Oil  Room.  All  oils,  grease,  benzine, 
etc.,  kept  in  barrels  should  be  stored  in  a  separate  room  for  two 
reasons,  one  being  to  avoid  leakage  due  to  the  prevailing  heat 
of  the  power  station,  and  the  other  to  confine  this  material  so  that 
it  will  be  less  exposed  to  fire,  and  thus  not  liable  to  endanger  other 
parts  of  the  building  in  case  a  fire  should  start  from  the  point  where 
such  inflammable  material  is  stored.  The  oil  room  should  have 
a  double  metal-faced  door,  one  inside  of  the  room,  and  the  other 
outside  of  the  room  or  wall.  The  room  should  be  located  at  an 
outside  wall,  with  sufficient  windows  opening  away  from  the 
building  to  act  as  a  vent  in  case  of  an  explosion  of  vapor  inside  of 
the  oil  room  and  also  to  allow  the  fire  to  be  suppressed  from  the 
outside.  The  ceiling  should  be  of  masonry,  designed  to  withstand 
intense  heat.  The  door  which  opens  into  the  oil  room  should 
have  a  masonry  sill  at  8  inches  or  more  above  the  floor,  so  that  if 
oil  should  escape  it  would  not  run  under  the  door  and  spread  the 


388  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

fire  to  the  rest  of  the  building.  A  sewer  and  catch  basin  should 
be  connected  to  the  oil  room  floor  to  carry  off  any  water  delivered 
to  the  room,  otherwise  both  water  and  oil  would  spread  to  other 
parts  of  the  building  by  leaking  through  the  crack  under  the  door. 

If  compressed  air  is  at  all  times  available  in  the  power  plant, 
a  very  efficient  system  of  fire  protection  can  be  provided  for  the 
oil  room  by  using  one  of  the  many  "kill  fire"  powders.  Such 
powder  can  be  stored  outside  of  the  oil  room  and  can  be  thrown 
on  the  fire  by  means  of  compressed  air.  The  use  of  water  in  an 
oil  room  tends  to  spread  fire,  but  the  chemical  powders  merely 
produce  a  non-combustible  gas,  which  smothers.  It  must  be 
borne  in  mind,  however,  that  fire  extinguishers  which  produce 
non-combustible  gases  are  only  successful  in  a  closed  space.  The 
necessity  for  keeping  the  doors  closed  when  these  powders  are  used 
will  therefore  be  evident.  A  closed  room  such  as  has  been  sug- 
gested for  the  storage  of  oil  is  ideally  suited  for  the  use  of  chemical 
fire  extinguishers,  since  the  air  is  confined  in  the  room,  and  the 
non-combustible  gas  is  easily  retained  and  accomplishes  results 
with  a  small  amount  of  chemical. 

Instead  of  using  dry  powder  it  might  be  better  to  use  bottles  of 
the  chemical  in  liquid  form,  supported  by  fuse  wire  or  strings,  so 
that  in  case  of  fire  the  bottles  would  drop  to  the  floor,  break,  and 
extinguish  the  blaze. 

If  compressed  air  is  not  available  in  the  plant  two  or.  three  pipe 
sleeves  can  be  built  in  the  oil  room  wall,  and  if  chemical  extin- 
guishers are  available  their  contents  can  be  discharged  into  the  oil 
room  through  the  sleeves. 

Engine  and  cylinder  oil  contained  in  metal  tanks  would  be  but 
a  slight  fire  risk  if  kept  between  the  masonry  foundations  if  there 
is  masonry  floor  in  the  engine  room  basement. 

Where  a  return-drip  oil  system  is  used  it  is  quite  objectionable 
to  place  any  part  of  this  system  in  the  oil  room.  It  is  seldom  a 
difficult  problem  to  place  the  various  parts  of  the  return-drip 
system  so  that  they  are  protected  from  the  fire.  If  the  engine  room 
floor  is  made  of  wooden  joists  and  wooden  boards  there  will  be 
little  additional  risk  if  oil  in  metal  tanks  is  placed  below  it.  The 
fire  would  have  to  be  far  beyond  control  before  there  would  be  any 
additional  danger  from  the  oil  tanks. 


CHAPTER    XXIII. 
WATER   TREATMENT    APPARATUS    AND    PIPING. 

Class  Nl  —  Water  Treatment  —  Water  Supply.  If  a  water 
treatment  plant  is  necessary  it  is  quite  evident  that  there  is  little  or 
no  choice  in  regard  to  the  water  which  is  to  be  used  for  the  steam 
plant.  Regardless  of  the  system  of  chemical  treatment  which  is 
used,  it  is  advisable,  if  not  absolutely  necessary,  that  the  tempera- 
ture of  the  water  be  raised  to  facilitate  the  treatment.  Nearly  all 
chemicals  soluble  in  water  dissolve  more  easily  as  the  temperature 
of  the  water  is  increased,  and  chemical  action  also  takes  place 
more  readily  in  warm  than  in  cold  solutions.  The  efficiency  of 
the  treating  apparatus  is  therefore  increased  if  it  is  kept  sufficiently 
warm.  If  the  plant  is  run  condensing,  then  the  water  should  be 
taken  from  the  hot-well. 

Three  different  chemical  treatment  systems  are  shown  in  Figs. 
63,  64,  65  and  66.  Fig.  63  shows  the  water  being  taken  from  the 
condenser  discharge  (this  being  the  regularly  used  connection),  and 
this  discharge  should  be  trapped  so  that  it  will  retain  the  water, 
even  in  case  there  is  little  or  no  flow  through  it.  Ordinarily  it  is 
the  best  practice  to  fill  the  precipitation  tanks  with  warm  water 
when  the  condenser  is  running. 

A  chemical-treating  plant  is  a  source  of  economy,  and  if  its 
operation  is  interfered  with,  the  loss  will  be  proportional  to  the 
time  it  is  out  of  service,  but  in  no  case  should  the  continuous 
operation  of  the  power  plant  be  dependent  upon  the  treating 
system.  If  it  is  possible  to  deliver  sufficient  steam  for  20  hr.  a  day 
to  raise  the  temperature  of  the  feed  water  to  200  degrees,  it  would 
be  poor  judgment  to  install  a  treating  system  sufficiently  large  to 
treat  cold  water. 

It  requires  careful  consideration,  however,  in  deciding  upon  the 
use  of  exhaust  steam  for  warming  the  purification  tank.  If  there 
is  but  a  limited  amount  of  exhaust  steam,  special  precautions 
should  be  taken  to  save  the  heat  units  in  the  exhaust,  and  it  would 
be  a  mistake  to  use  exhaust  steam  in  such  cases  for  heating  the 

389 


390 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


treating  tank  in  order  to  permit  the  use  of  a  less  expensive  installa- 
tion than  would  be  possible  if  the  water  were  treated  cold.  Far 
more  money  would  be  lost  in  heat  radiation  from  the  tanks  than 
would  be  required  to  pay  the  interest  and  depreciation  charges  on 
a  treating  plant  sufficiently  large  to  treat  cold  water  which  would 
not  give  rise  to  the  loss  by  radiation. 

A  very  efficient  plan  of  raising  the  temperature  of  the  mixing 
tank  is  that  shown  in  Fig.  306  (Ni-i ).  In  the  arrangement  shown 
there  is  not  so  great  a  heating  surface  exposed  to  the  flue  gases  as 


ty/toton  A&ec#>t/0/)cn 

FIG.  306  (Ni-i). 


there  would  be  in  an  economizer,  but  this  is  not  objectionable, 
because  it  would  be  quite  undesirable  to  raise  the  temperature  of 
the  water  above  about  200  degrees,  otherwise  vapor  would  be  given 
off.  In  the  plant  shown  in  Fig.  306  there  are  two  tanks  side  by  side, 
with  flue  dampers  which  can  be  opened  and  closed  to  shut  off  the 
gases  from  either  tank. 

Ample  space  should  be  left  around  the  tank  for  cleaning  out  and 
making  repairs.  When  the  heat  is  applied  it  may  be  found  neces- 
sary to  use  the  three  tanks  so  that  the  circulation  of  the  water  may 
be  stopped  to  allow  the  material  to  precipitate. 

When  a  tank  is  rilled  with  water,  the  chemicals  are  run  into  it 
and  the  mixer  is  started.  The  mixer  should  run  as  long  as  the 
flue  gases  are  passing  around  the  tank  to  keep  the  water  in  circu- 
lation. The  flue  gases  should  pass  around  but  one  tank  at  a  time. 
One  of  the  other  tanks,  just  previously  agitated,  should  be  shut 
down  to  settle,  ready  for  supplying  water.  There  would  be  three 


WATER   TREATMENT   APPARATUS  AND   PIPING.          39! 

operations  to  be  carried  out  by  each  shift  of  operators  —  agitation, 
precipitation,  and  supply. 

The  time  required  to  change  the  tanks  is  a  very  small  item  if 
the  necessity  for  watching  it  be  eliminated.  This  difficulty  can  be 
overcome  quite  readily  by  attaching  an  alarm  to  the  suction  pipe 
in  the  tank  having  a  float  at  its  movable  end,  as  shown  in  Fig.  63. 
The  alarm  will  notify  the  operator  when  the  tank  is  pumped  full 
and  also  when  the  tank  being  drawn  from  is  empty.  Such  a 
system  of  water  treatment  is  very  efficient  because  the  water  is  at 
rest  for  so  long  periods  of  time.  When  the  tanks  are  changed  every 
8  hours  it  will  be  necessary  to  make  them  20  ft.  in  diameter  and 
14  ft.  high  for  a  i,ooo-boiler  hp.  plant.  If  the  continuous  system 
shown  in  Fig.  65  were  to  be  heated  by  waste  flue  gases  it  would 
be  necessary  to  use  a  separate  tank  for  mixing  and  agitation,  other- 
wise but  little  heat  would  be  taken  up  by  the  water. 

When  the  feed  water  is  heated  as  shown  in  Fig.  306  there  will  be 
but  little  use  for  exhaust  steam,  and  it  will  be  found  to  be  a  more 
economical  arrangement  to  run  the  air  and  circulating  pumps  for 
the  condenser  from  the  engine  shafting  or  use  a  motor-driven 
centrifugal  pump.  The  feed  pump  should  be  compounded  and 
a  small  closed  heater  used  to  condense  its  steam.  The  pump 
used  to  fill  the  heating  tanks  may  be  of  the  motor-driven  centrifugal 
type.  A  plant  equipped  in  this  manner  will  show  very  good  econ- 
omy, the  tanks  located  in  the  smoke  flue  effecting  a  saving  the 
same  as  economizers  would,  but  without  offering  an  equal  obstruc- 
tion to  the  draft.  The  saving  in  chemicals  alone  is  a  great  advan- 
tage with  the  heating  tanks,  and  whatever  heat  is  transferred  from 
the  flue  gases  to  the  water  there  would  be  as  much  of  a  saving  as 
from  economizers. 

Class  N2  —  Water  Treatment  Boiler  Supply.  The  water  from 
the  treating  tank  or  apparatus  should  only  be  connected  to  feed 
pump  suctions  which  can  readily  be  shut  off  without  interfering 
in  the  least  with  the  running  of  the  pump.  The  treating  pump 
should  be  arranged  the  same  as  though  it  were  merely  a  conven- 
ience, the  loss  occasioned  by  shutting  it  down  being  too  slight  to 
justify  any  expense  in  providing  emergency  arrangements  to 
insure  its  continuous  operation. 

The  feed  pump  should  have  a  suction  direct  from  the  hot-well 
and  also  one  from  the  intake.  These  different  connections  are 
clearly  shown  in  Figs.  64  and  65.  The  discharge  from  the  feed 


392  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

pump  to  the  boiler  is  the  same  as  for  any  other  water  supply.  It 
is  only  in  the  pressure  system  shown  in  Fig.  66  that  the  water 
treatment  apparatus  is  located  between  the  pumps  and  boilers. 
In  this  case  the  treating  system  is  operated  in  much  the  same 
manner  as  a  closed  heater. 

There  is  one  point  which  must  constantly  be  borne  in  mind  in 
considering  chemical  treatment,  and  that  is  how  to  remove  the 
impurities  from  the  water  before  it  is  taken  into  the  pump  suction. 
The  velocity  of  the  water  in  a  pressure  system  is  quite  rapid  because 
of  the  smaller  size  of  the  water  tanks  which  must  be  used  in  order 
to  withstand  the  boiler  pressure.  To  accomplish  the  same  results 
as  are  obtained  with  larger  precipitation  tanks  a  filter  bed  must  be 
used.  To  facilitate  a  precipitation  it  is  necessary  that  no  water 
flow  in  or  out  of  the  tank,  and  that  no  mixer  or  other  device  be  in 
motion  while  the  process  of  settling  is  taking  place. 

There  is  still  another  condition  which  will  prevent  the  successful 
operation  of  a  precipitation  plant  and  that  is  caused  by  varying 
temperatures  of  the  water.  Circulation  of  the  water  prevents  the 
precipitate  from  settling.  In  a  steam  boiler  circulation  serves  a 
useful  purpose  and  partially  prevents  exactly  what  is  desired  in  a 
precipitating  tank.  For  instance,  if  heat  is  applied  to  the  under 
side  of  the  tank  shown  in  Fig.  306,  circulation  of  the  water  will  be 
set  up.  Also,  if  the  surface  of  the  water  is  exposed  to  a  cold  atmos- 
phere circulation  of  the  water  will  likewise  take  place.  For  these 
reasons  the  gases  must  be  shut  off  from  the  tank  while  precipitation 
and  settling  are  taking  place.  By  permitting  the  bottom  of  the 
tank  to  become  cooler  than  the  top  circulation  is  also  prevented. 

It  is  desirable  to  have  water  in  the  boiler  circulating  at  all  times 
to  prevent  the  fine  impurity  from  settling.  There  are  times, 
however,  when  the  circulation  in  the  boiler  is  sluggish,  and  then  the 
finely  divided  precipitate  settles  on  the  tubes  and  other  parts  of  the 
boiler.  The  amount  of  precipitation  which  will  settle  depends 
upon  the  length  of  time  the  circulation  is  retarded.  The  amount 
of  scale  which  is  formed  each  time  the  circulation  in  the  boiler  is 
retarded  is  easily  seen  by  counting  the  number  of  laminations  in 
the  scale  and  noting  the  thickness  of  each.  Scale  0.5  in.  thick 
may  be  made  up  of  a  number  of  equal  laminations,  or  it  may  be 
composed  of  one  lamina  0.25  in.  thick  and  a  number  of 
thinner  ones  in.  or  less  in  thickness.  A  piece  of  scale  thus 
laminated  would  indicate  that  the  boiler  had  been  banked  for  one 


WATER   TREATMENT  APPARATUS  AND   PIPING.          393 

long  period  and  a  number  of  shorter  ones,  or  it  may  indicate  that 
more  scale-forming  material  entered  the  boiler  during  one  period 
than  at  another. 

The  precipitation  of  the  impurities  in  feed-water  is  much  the  same 
whether  the  process  is  carried  out  in  a  settling  tank  or  in  a  boiler. 
The  heat  or  chemicals  will  liberate  the  gas  which  is  necessary  to 
hold  the  impurities  in  the  solution,  and  the  problem  at  all  times 
resolves  itself  into  that  of  freeing  the  material  of  this  gas  and  pre- 
cipitating the  impurities  before  the  water  enters  the  boiler.  The 
use  of  compounds  or  chemicals  which  precipitate  the  impurities 
in  the  boiler  is  extremely  objectionable,  because  all  the  impurities 
are  thus  delivered  into  the  boiler  and  in  addition  the  chemicals 
which  are  used  to  throw  down  the  scale-forming  salts. 

In  order  to  operate  a  boiler  with  such  mud  in  it,  it  is  necessary 
to  constantly  throw  away  part  of  the  boiler  water  by  blowing  off 
and  to  thin  down  the  salts  left  in  the  boiler  by  the  addition  of  fresh 
water.  This  is  necessary  to  prevent  foaming  and  priming,  which 
would  make  the  quality  of  the  steam  very  poor  and  might  cause 
serious  injury  to  the  engines. 

Exhaust  and  live  steam  purifiers  are  troublesome  devices  to 
operate  and  are  generally  of  such  small  dimensions  that  the  water 
flows  through  them  at  a  relatively  high  rate  and  therefore  does  not 
permit  the  suspended  material  to  be  completely  settled.  Though 
live  steam  purifiers  may  liberate  the  gas  which  holds  the  salts  in 
solution,  they  have  not  sufficient  volume  to  permit  so  complete  a 
separation  of  the  suspended  material  as  is  obtained  in  two  2O-ft. 
tanks. 

Live  steam  purifiers  are  really  only  continuous  heaters,  and  as 
insufficient  time  is  allowed  for  settling,  it  is  necessary  to  use  a  filter 
in  conjunction  with  them,  the  same  as  for  the  high-pressure  closed 
continuous  chemical  treatment  system.  Precipitation,  however, 
will  remove  impurities  more  effectively  than  is  possible  by  any 
other  means.  Water  and  oil  will  pass  through  a  filter  bed  of  the 
finest  material  without  any  sign  of  one  being  separated  from  the 
other,  and  this  is  likewise  true  of  water  carrying  an  impalpable 
powder  in  suspension,  since  the  latter  will  pass  through  any  filter 
or  screen  through  which  water  will  pass. 

A  filter  is  merely  a  screen  which  removes  the  larger  particles 
and  permits  the  smaller  ones  to  pass.  Precipitation,  however, 
separates  the  heavier  from  the  lighter  material,  regardless  of  its 


394 


STEAM  POWER   PLANT  PIPING  SYSTEMS. 


ability  to  pass  through  a  mesh  of  a  certain  gage.  The  separation 
in  this  case  is  due  to  the  difference  in  the  specific  gravities  of  the 
water  and  suspended  materials.  Oil  and  water  will  quickly 
separate  if  permitted  to  precipitate,  though  a  filter  would  have  no 
effect  whatever.  If  sufficient  time  is  allowed  material  suspended 
in  water  will  precipitate  regardless  of  how  finely  it  may  be  divided, 
but  if  sufficient  time  is  not  given  for  precipitation,  then  there  is  no 
means  for  separating  it  from  the  water  other  than  by  filtration  or 
by  attraction.  The  latter  means  of  separation  is  the  one  prin- 
cipally used  in  live  steam  purifiers. 

A  steam  purifier  of  the  tray  type  is  shown  in  Fig.  307  (N2-i). 
These  trays  are  so  arranged  that  they  can  be  drawn  from  the 
purifier  lengthwise,  thus  permitting  the  scale  which  has  been 


from  ft/mp        < 


FIG.  307  (Nz-i). 


FIG.  308  (N3-i). 


deposited  on  them  to  be  easily  removed.  Each  tray  is  supported 
the  same  as  a  drawer,  by  two  guides.  The  water  flows  into  the 
top  tray  and  overflows  at  the  edges.  Instead  of  dripping  over  the 
edge,  it  runs  along  the  bottom  and  drips  into  the  next  lower 
tray,  and  thus  discharges  from  one  to  another.  A  part  of  the 
soluble  salts  is  precipitated  in  the  trays,  though  the  largest  amount 
of  precipitate  is  found  just  under  the  edges  of  the  trays.  That  which 
is  caught  is  dried  and  baked  on  to  the  pan,  the  same  as  boiler 
scale  forms  in  a  boiler,  only  it  is  deposited  in  a  far  less  uniform 
manner.  The  scale  which  forms  on  the  under  side  of  the  tray 
is  caught  neither  by  precipitation  nor  by  filtration,  but  simply  by 
attraction,  there  evidently  being  a  strong  affinity  between  the 
scale  which  has  formed  and  that  suspended  in  the  water.  The 
temperature  in  the  purifier  is  generally  much  greater  than  that  at 
which  the  sulphates  remain  in  solution,  i.e.,  270°  F.,  the  result 
being  that  the  scale  which  collects  is  very  solid. 


WATER   TREATMENT  APPARATUS  AND   PIPING.          395 

Class  N3  —  Water  Treatment  after  Reaching  the  Boiler.  There 
are  numerous  forms  of  boiler  water  purifiers,  most  of  which  are 
of  the  general  type  shown  in  Fig.  308  (N3~i).  The  water  is  taken 
from  the  boiler  and  discharged  into  a  small  settling  tank  and 
returned  to  the  boiler,  the  circulation  being  maintained  by  running 
a  hot  pipe  inside  the  furnace,  as  shown  at  A . 

There  are  various  forms  of  pipe  connections  used,  in  all  of 
which  are  arranged  cold  and  hot  legs,  thus  making  one  column 
of  water  heavier  than  the  other.  There  is  a  swivel  at  B,  and 
float,  C,  to  move  the  skimmer  up  and  down  as  the  water  level 
changes.  The  skimmer  serves  to  remove  some  of  the  lighter 
impurities  that  are  on  the  surface  of  the  water.  These  impurities 
generally  make  the  thickest  scale,  but  the  scale  formed  by  them 
is  soft  and  spongy  and  easily  broken.  By  removing  this  material 
and  leaving  the  heavier  sulphates  the  scale  that  forms  on  the 
boiler  is  extremely  hard.  It  frequently  requires  more  time  to 
remove  this  hard  scale  than  it  would  to  remove  the  heavier  scale 
which  would  have  formed  had  the  lighter  material  not  been 
removed. 

Not  only  does  it  require  more  time  to  remove  the  hard  scale, 
but  the  wear  and  tear  on  the  tube  cleaners  is  of  serious  importance. 
Water  which  does  not  contain  the  sulphates  which  form  hard  scale 
is  rarely  found,  but  water  which  contains  little  else  than  carbonate 
of  lime  and  magnesia  may  be  greatly  improved  by  the  use  of  such 
devices.  The  fine  impurities  which  are  constantly  being  carried 
around  by  the  circulation  of  the  water  are  not  removed  by  surface 
skimmers,  the  only  method  of  removing  these  being  to  permit  the 
water  to  come  to  absolute  rest  and  give  it  sufficient  time  to  settle. 

The  tank,  Z>,  is  designed  for  this  purpose,  and  its  efficiency  is 
dependent  wholly  upon  its  size.  The  blow-off,  E,  is  intended 
to  discharge  the  scum  or  light  impurities,  and  the  precipitate  is 
drawn  off  through  the  valve,  F.  The  principle  involved  in  the 
operation  of  this  device  shown  in  Fig.  308  is  identical  with  the 
action  taking  place  in  all  boilers.  The  circulation  of  a  small 
portion  of  the  water  is  retarded,  and  this  permits  a  partial  separa- 
tion to  take  place. 

Where  the  circulation  is  thus  retarded  the  greatest  amount 
of  scale  is  formed  in  the  boiler.  These  settling  places  or  mud 
drums  are  practically  the  same  as  the  tank  shown  in  Fig.  308. 
They  are  far  too  small  to  insure  any  appreciable  good.  A  5oo-hp. 


396 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


boiler  would  be  provided  with  a  tank  about  2  ft.  in  diameter  and 
5  ft.  high,  thus  holding  about  1,000  Ib.  of  water,  the  latter  being 
equal  to  that  which  is  evaporated  in  4  min.  To  permit  these 
fine  impurities  to  precipitate,  the  flow  through  the  tank,  D,  should 
be  very  slow,  the  most  satisfactory  result  being  obtained  when  there 
is  no  flow  whatever.  Chemical  treating  plants  are  able  to  show 
good  results  because  of  this  fact  alone,  and  as  the  velocity  is 
increased  the  amount  of  impurities  which  are  precipitated  decreases 
and  thus  a  filter  bed  becomes  necessary. 

If  the  system  shown  in  Fig.  308  were  carried  out  on  a  sufficiently 
large  scale  to  accomplish  the  desired  result  of  removing  a  sufficient 


FIG.  309  (N3-2). 

amount  of  scale-forming  impurities,  it  would  be  a  far  superior 
arrangement  to  any  which  is  in  use.  It  would  then  accomplish 
the  desired  results  without  the  addition  of  any  chemicals  to  the 
water  in  the  boiler. 

In  Fig.  309  (N3-2)  a  precipitating  tank  is  shown  placed  beneath 
the  boiler.  Water  is  taken  from  the  surface  of  the  boiler.  This 
removes  the  impurities  carried  by  the  water  which  is  in  circulation. 
The  feed  water  drives  the  circulator  and  thus  causes  all  the  water 
in  the  boiler  to  circulate  through  the  settling  tank  and  back  to  the 
boiler.  For  each  gallon  of  water  fed  into  the  boiler  an  equal 
amount  of  water  from  the  boiler  circulates  through  the  tank. 
The  enlarged  detail  shows  how  the  blow-off  is  taken  from  along 
the  entire  length  of  the  tank  bottom.  As  considerable  scale  will 
form  where  the  feed  water  enters,  a  cap,  C,  closes  the  end  of  the 
brass  distribution  pipe  and  facilitates  the  removal  of  scale. 


WATER   TREATMENT  APPARATUS  AND  PIPING.          397 

If  the  boiler  pressure  is  140  lb.,  the  temperature  of  the  water  in 
the  boiler  is  350  degrees,  and  if  the  temperature  of  the  incoming 
feed  water  is  200  degrees  the  temperature  of  the  feed  water  will  be 
raised  to  280  degrees.  This  is  sufficient  to  throw  down  the  sul- 
phates. The  latter  calculation  is  based  on  the  assumption  that 
for  each  gallon  of  water  fed  to  the  boiler  one  gallon  of  the  water 
in  the  boiler  is  circulated  through  the  treating  tank. 

It  should  be  remembered  that  the  smaller  the  amount  of  boiler 
water  which  is  circulated,  the  more  efficient  the  filter  bed  becomes. 
The  circulating  device  shown  would  not  be  fitted  with  stuffing 
boxes.  It  would  deliver  its  water  under  a  slightly  greater  head 
than  its  suction.  The  parts  of  this  device  would  be  fitted  loosely 
and  its  service  would  be  very  light.  Manholes  should  be  fitted 
in  the  outside  end  of  the  tank  and  a  valve,  D,  provided  to  shut  off 
the  water  to  the  under  side  of  the  filter  bed.  Hence  by  opening 
the  blow-off  valve,  £,  the  deposit  in  the  filter  bed  would  be  easily 
discharged  into  the  sewer.  The  gage,  F,  shows  a  difference  in 
pressure  above  and  below  the  filter  bed,  and  thus  as  the  filter  bed 
becomes  fouled  the  pressure  gage  enables  the  operator  to  know 
definitely  when  it  is  necessary  to  blow  it  out.  As  little  or  no  heat 
is  applied  to  the  tank  there  will  be  no  tendency  to  form  scale,  the 
impurities  settling  in  the  form  of  mud. 

The  covering  over  the  tank  should  be  supported  either  on  an 
arch  or  on  T-bars,  as  shown  in  Fig.  309.  When  the  tank  extends 
to  the  back  wall  the  wall  should  have  the  form  of  an  arch  about  an 
inch  distant  from  the  tank.  The  space  between  the  tank  and  the 
wall  should  be  closed  with  asbestos  to  prevent  any  air  leaking  into 
the  furnace.  The  tank  shown  in  Fig.  309  has  fully  ten  times  the 
capacity  of  that  shown  in  Fig.  308,  and  in  addition  it  also  has  a 
filter  across  its  widest  section  where  the  velocity  of  the  water  is  the 
least. 

To  apply  such  a  purifier  to  a  Babcock  &  Wilcox  type  of  boiler, 
it  may  be  necessary  to  place  it  transversely  instead  of  longitudinally 
as  shown,  or  it  may  be  placed  outside  of  the  setting.  The  only 
object  in  placing  it  inside  the  setting  is  to  reduce  the  radiation  from 
it.  The  purifier  shown  is  a  part  of  the  boiler,  being  out  of  service 
whenever  the  boiler  is  not  being  used,  and  there  would  thus  be 
ample  opportunity  at  such  times  to  examine  or  clean  the  purifier. 
This  precipitation  tank  would  require  frequent  blowing  out,  but 
the  time  required  for  this  operation  would  be  very  slight.  It  does 


39$  STEAM   POWER  PLANT  PIPING   SYSTEMS. 

not  become  a  repository  for  scale  as  in  the  case  of  live  steam 
purifier. 

The  velocity  through  the  filter  shown  in  Fig.  309  would  be  about  3 
feet  per  hour  if  none  of  the  area  were  occupied  by  filtering  material, 
but  as  the  area  through  a  filter  bed  is  only  about  25  per  cent  of 
the  total  area  of  the  filter,  the  velocity  through  the  filtering  material 
will  be  about  12  ft.  per  hour.  A  filter  bed  used,  as  shown  in  Fig. 
309,  is  not  subjected  to  the  same  exacting  requirements  as  the  one 
used  in  the  chemical  system  shown  in  Fig.  66.  In  the  filter  shown 
in  Fig.  309  the  water  is  constantly  being  repassed  through  the  filter, 
and  if  the  filter  bed  does  not  remove  the  extremely  fine  particles 
but  little  harm  will  result  from  their  presence,  since  the  water  must 
be  practically  at  rest  before  they  will  settle. 

Filters  such  as  shown  in  Fig.  66  ordinarily  have  about  i  square 
foot  of  filter  bed  for  each  30-hp.  capacity.  That  shown  in  Fig. 
309  has  about  J  sq.  ft.  per  hp.,  but  as  it  must  pass  boiler  water  as 
well  as  the  feed  water,  the  area  may  be  anywhere  from  0.08  to 
o.i  66  sq.  ft.  per  hp. 

Class  N4  —  Water  Treatment  Minor  Connection.  Intermittent 
chemical  treating  systems  require  a  considerable  amount  of  piping 
for  their  installation,  due  largely  to  the  fact  that  separate  pumps 
and  heaters  are  generally  required.  In  the  water  treating  plant 
the  pump  is  used  solely  in  forcing  water  into  the  large  tank.  Steam 
may  be  brought  from  the  main  station  to  the  chemical  building,  and 
instead  of  exhausting  the  pump  into  the  main  heater,  the  steam  from 
the  pump  may  be  fed  to  a  heater  to  be  used  for  raising  the  tem- 
perature of  the  water  before  it  is  delivered  into  the  treating  tank. 

In  addition  to  the  steam  line  to  the  treating  plant  there  would 
be  a  line  from  the  condenser  discharge  and  a  line  from  the  intake. 
A  pipe  also  would  be  required  for  delivering  treated  water  to  the 
boiler  feed  pump  in  the  power  house.  If  the  treating  tanks  are 
placed  more  than  14  ft.  below  the  feed  pump  and  an  open  heater 
is  used,  the  discharge  from  the  tank  should  be  run  at  a  low  eleva- 
tion to  a  pump  located  as  shown  in  Fig.  310  (N4~i).  The  steam 
supply  to  this  pump  is  controlled  by  a  ball  float  operated  valve 
located  at  the  heater,  as  shown. 

If  an  open  heater  is  used,  this  system  of  controlling  the  water  to 
the  heater  is  very  satisfactory,  and  in  most  cases  permits  the  use  of 
a  standard  pump  with  the  water  cylinder  on  the  level  of  the  boiler 
room  floor.  Only  in  exceptional  cases  would  the  water  supply  be 


WATER   TREATMENT  APPARATUS  AND   PIPING. 


399 


so  far  below  the  boiler  room  floor  that  it  would  necessitate  placing 
the  water  end  in  the  well,  as  shown  in  Fig.  310. 

The  bottom  of  the  precipitation  tank  should  be  far  enough  above 
the  supply  water  line  to  insure  an  ample  drop  for  the  wash-out 
line  which  is  used  for  discharging  the  precipitate.  There  should 
be  hose  connections  to  the  pump  in  the  chemical  house,  as  it  is 
necessary  to  wash  out  the  settling  tanks.  These  tanks  should  not 
be  washed  out  very  often,  since  it  is  found  in  practice  that  the 


FIG.  310  (N4-i). 

agitation  of  the  old  sludge  aids  in  carrying  down"  "the  finer  pre- 
cipitate when  it  is  first  formed,  and  it  therefore  is  beneficial  to  keep 
some  of  the  old  mud  in  the  tanks  at  all  times. 

Fig.  310  shows  a  water  tank  constructed  of  concrete.  Before 
deciding  upon  the  use  of  concrete  for  this  purpose  it  would  be  well 
to  submit  the  concrete  materials  to  a  chemist,  together  with  a 
sample  of  the  water.  The  decision  to  use  such  materials  would 
depend  upon  the  character  of  the  water  and  the  reagents  necessary 
to  treat  it.  Wood  is  very  extensively  used  for  chemical  treating 
tanks,  as  iron  deteriorates  rapidly.  In  any  case  the  tanks  should 
be  round  in  shape  with  a  mechanically  driven  agitator  (motor- 
driven  or  otherwise). 

Cold  water  must  be  agitated  longer  than  warm  water.  Water 
at  35  degrees  must  be  agitated  for  about  three  hours  to  complete 
the  chemical  reactions  and  about  1.5  hr.  at  90  degrees  and  about 
one  hour  at  170  degrees.  If  the  tanks  are  not  continuously 


40O  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

agitated  while  chemical  action  is  taking  place,  the  chemicals  fall 
to  the  bottom  and  thus  a  large  proportion  of  the  chemicals  is 
wasted.  If  the  water  is  brought  to  a  state  of  rest  the  precipita- 
tion is  quite  rapid,  15  min.  generally  being  sufficient. 

A  complete  plant  for  treating  600,000  gal.  of  water  per  day 
costs  about  $10,000.  Ordinarily  the  total  cost,  including  interest 
on  the  investment,  depreciation,  labor,  materials,  etc.,  is  from 
two  to  five  cents  per  1,000  gal.  of  water  treated,  depending  upon 
the  character  of  the  water,  chemicals  required  and  the  amount  of 
labor  needed  to  operate  the  plant.  Assuming  a  cost  of  four  cents 
per  i,ooo  gal.  for  treating  the  water  and  that  the  plant  is  run  at  its 
full  capacity  16  hr.  a  day  for  30  days,  the  total  cost  of  treating  the 
water  (1,920,000  gal.)  would  be  about  $75,  provided  that  special 
employees  were  not  needed  to  operate  the  treating  plant. 

A  chemical  treating  plant  for  1,000  hp.  capacity  would  be  much 
smaller  than  the  6oo,ooo-gal.  plant  previously  mentioned,  and 
therefore  the  cost  of  installation  per  gallon  of  capacity  would  be 
somewhat  greater.  Boilers  of  1,000  hp.  capacity  require  4,000  gal. 
of  water  per  hr.  Consequently,  if  the  tanks  are  changed  every 
8  hr.  they  must  have  a  capacity  of  32,000  gal.  each  or  96,000  gal. 
per  day.  The  portion  of  the  tanks  holding  water  would  then  be 
about  20  ft.  in  diameter  and  14  ft.  high. 

These  tanks  would  have  double  the  capacity  if  the  water  were 
changed  every  4  hr.  instead  of  every  8  hr.  The  chemical  holding 
tank  should  be  round,  as  the  circular  form  of  tank  is  best  suited 
to  use  in  conjunction  with  an  agitator.  If  a  tank  is  required 
for  mixing  the  chemicals  before  they  are  fed  into  the  precipitating 
tank,  the  water  fed  into  the  precipitating  tank  should  be  passed 
through  the  chemical  measuring  device  and  from  there  into  the 
large  tank,  thus  insuring  that  all  the  chemicals  weighed  out  are 
emptied  into  the  precipitating  tank. 

Instead  of  using  a  steam  pump  to  fill  the  tank  a  centrifugal 
pump  driven  from  a  line  shaft  connected  to  a  small  engine  may  be 
used.  This  line  shaft  may  also  drive  the  agitators.  The  exhaust 
from  this  engine  may  be  delivered  directly  into  the  water  at  the 
side  of  the  tank,  the  heat  thus  being  taken  up  during  the  entire 
time  the  water  is  being  agitated  as  well  as  when  the  tanks  are 
being  filled.  The  pump  and  agitators  should  be  fitted  with 
clutches  or  tight  and  loose  pulleys  so  that  either  can  be  run  without 
the  other. 


WATER   TREATMENT  APPARATUS  AND   PIPING.        40 1 

If  a  station  operator  has  trouble  with  boilers  on  account  of  the 
impure  feedwater,  it  is  advisable  that  he  learn  all  he  can  about 
chemical  treatment  before  making  any  definite  decisions  or 
letting  contracts.  The  manufacturing  chemists  should  analyze 
the  water,  state  its  properties,  the  reagents  to  use,  quantity  of  each 
which  are  necessary,  and  submit  a  price  for  the  reagents.  From 
time  to  time  after  a  treating  plant  has  been  installed  it  will  be 
advisable  to  send  a  sample  of  untreated  and  a  sample  of  treated 
water  to  the  chemist's  works  to  determine  if  the  proper  kind  and 
quantity  of  reagents  are  being  used  and  to  determine  if  the  reagents 
being  used  are  giving  the  best  results. 

The  successful  operation  of  any  water  treating  plant  is  dependent 
almost  wholly  upon  the  chief  operator,  and  if  it  is  necessary  for 
him  to  become  thoroughly  familiar  with  this  subject  why  should 
not  this  information  be  secured  before  planning  the  installation 
of  a  plant  ?  If  the  chief  operator  has  no  other  means  of  obtaining 
the  information  desired,  it  would  no  doubt  prove  to  be  a  good 
investment  to  install  a  small  vertical  internally  fired  boiler  in  the 
boiler  room  within  easy  reach  of  the  firemen.  This  small  boiler 
need  not  be  over  10  hp.  and  should  be  connected  to  one  of  the 
regular  steam  mains.  A  separate  pump  should  be  installed  for 
feeding  this  boiler  with  treated  water  prepared  in  a  small  experi- 
mental treating  plant  consisting  of  a  couple  of  temporary  tanks. 

The  expense  of  such  an  experimental  plant  would  be  very 
slight,  as  the  boiler  could  probably  be  rented  and  one  of  the 
spare  pumps  piped  temporarily  for  feeding  the  small  boiler.  It  is 
highly  probable  that  after  using  the  experimental  plant  for  a  month 
or  two  the  employees  operating  it  would  be  familiar  with  chemical 
treatment  and  any  decision  which  might  then  be  made  regarding 
a  permanent  installation  would  be  based  on  a  definite  knowledge 
of  the  conditions  and  would  undoubtedly  be  correct. 


CHAPTER    XXIV. 
HIGH    PRESSURE    WATER    PIPING. 

Classes  Ol  to  O3  —  Water  to  Hydraulic  Elevators.  If  elevators 
are  installed  in  a  power  house  they  are  generally  of  the  hydraulic 
ram  construction  termed  "lifts,"  generally  low  lifts  only,  such  as 
from  the  boiler  room  basement  to  boiler  room  floor  level,  a  height 
of  10  to  20  ft.  The  elevator  platform  is  placed  on  the  end  of  a 
plunger  and  the  cylinder  is  dropped  into  a  well  or  casing.  The 
valve  used  to  admit  and  discharge  water  from  the  ram  is  generally 
of  the  balanced  piston  type  with  cup  leather  washers  such  as  are 
used  on  heavy  hydraulic  rams.  This  valve  is  quite  easily  operated 
and  permits  the  use  of  large  port  openings. 

For  boiler  room  service  the  pipe  connection  from  the  operating 
valve  to  the  elevator  cylinder  and  the  discharge  line  from  the 
elevated  cylinder  should  each  be  about  one-fourth  the  diameter 
of  the  plunger  if  the  pressure  carried  at  the  pump  is  60  Ib.  If 
high-pressure  water  is  available,  say  at  120  Ib.,  it  can  be  used  very 
satisfactorily.  The  use  of  warm  water  at  125  degrees  or  over 
should  be  avoided  if  possible,  as  the  stuffing  box  packing  and  cup 
leather  in  the  operating  valve  deteriorate  rapidly  when  warm 
water  is  used.  The  reason  for  this  is  that  the  heat  removes  the 
lubricant  from  the  packing.  A  standard  three-way  valve  can  be 
used  for  an  operating  valve,  but  is  much  more  difficult  to  move 
and  will  leak  considerably  if  it  is  used  frequently. 

In  the  construction  of  a  hydraulic  ram  it  is  the  best  practice  to  fit 
a  brass  sleeve  on  the  ram  which  passes  through  the  stuffing  box, 
but  unless  the  brass  sleeve  is  properly  fitted  considerable  difficulty 
and  annoyance  will  be  occasioned  by  leakage.  In  no  case  should 
the  joint  between  the  brass  tube  and  the  ram  be  made  tight  at  its 
outer  or  upper  end.  The  inner  end  should  be  made  tight  and  the 
outer  end  should  be  left  free  to  move  and  discharge  any  water 
that  may  have  leaked  by  the  inner  end,  thereby  avoiding  the 
possibility  of  the  pressure  inside  the  tube  causing  a  rupture. 
Considerable  difficulty  is  experienced  if  the  upper  end  of  the  brass 

402 


HIGH  PRESSURE   WATER   PIPING. 


403 


sleeve  is  rigidly  attached  to  the  iron  ram,  because  the  expansion  and 
contraction  of  iron  and  brass  are  not  the  same.  This  unequal 
expansion  and  contraction  causes  the  joint  at  the  inner  or  bottom 
end  of  the  ram  to  leak  and  make  trouble.  The  same  difficulty  is 
experienced  if  the  brass  sleeve  bears  against  a  shoulder  on  the  ram 
at  its  upper  end.  A  much  better  construction  is  obtained  if  the 
upper  end  of  the  brass  tube  is  free  to  expand 
and  contract,  and  to  secure  this  the  upper  end 
of  the  ram,  where  the  brass  tube  ends,  should 
have  a  slight  groove  turned  in  it,  as  shown 
in  Fig.  311  (Oi-i).  The  tube  can  be  placed 
on  the  ram  and  the  lower  end  "spun"  into 
the  shape  as  shown. 

One  of  the  most  useful  applications  of  the 
plunger  hydraulic  elevator  is  for  coal  and  ash 
lifts  in  small  stations.     The  general  plan  for 
installing  a  plunger  elevator  in  a  small  power 
house  is  shown  in  Fig.  312  (Oi-2).     In  such 
an  installation  the  hydraulic  elevator  would  lift  the  coal  car  about 
seven  feet.     The  weight  of  the  car  would  be  about  1,000  Ib.  and 
the  car  would  $be  loaded  with  from  1,000  to  1,500  Ib.  of  coal. 


FIG.  311  (Oi-i). 


FIG.  312  (Oi-2). 

For  a  boiler  plant  averaging  1000  hp.  about  100  trips  per  day 
would  be  required  for  handling  the  coal  used  in  a  2O-hr.  day, 
and  about  20  trips  would  be  required  to  remove  the  ashes.  The 
total  number  of  trips  per  day  would  therefore  be  about  120  in 
20  hr.,  or  about  6  trips  per  hr. 


404  STEAM  POWER  PLANT  PIPING   SYSTEMS. 

In  practice  it  has  been  found  that  one  man  on  each  shift  can 
handle  coal  and  ashes  of  the  quantity  stated  and  also  weigh  each 
car  of  coal.  Ordinarily  the  coal  is  shoveled  but  once  —  from  the 
car  to  the  overhead  bin.  The  storage  space,  which  requires  addi- 
tional shoveling  to  load  the  coal  into  the  small  cars,  is  used  only 
in  case  of  shortage.  The  ash  car  can  be  placed  either  on  a  coal 
track  or,  if  the  conditions  will  permit,  at  the  end  of  the  overhead 
track  that  runs  over  the  furnace  hopper.  This  track  is  extended 
over  the  railroad  ash  car  which  is  left  standing  on  a  stub 
switch. 

The  capacity  of  the  daily  storage  bin  should  be  slightly  greater 
per  foot  of  length  than  that  of  a  railroad  coal  car.  The  small 
cars  have  a  drop  front,  which  facilitates  loading  them  with  ashes 
from  the  floor,  and  they  are  also  fitted  with  dump  bottoms.  Scales 
are  provided  so  that  tests  of  a  certain  coal  or  boiler  can  readily 
be  made.  Ashes  are  delivered  to  the  small  car  while  it  is  on  the 
boiler  room  floor  level.  The  only  power  device  required  for  this 
entire  system  is  therefore  the  hydraulic  lift,  and  the  best  practice 
is  to  use  low-pressure  water  service  for  the  ram  if  the  station  has  its 
own  water  supply  or  has  a  storage  tank  into  which  the  ram  can 
discharge  if  city  water  is  used.  t 

If  an  open  heater  is  used,  fitted  with  a  float  admission  valve 
to  carry  low  water  in  the  heater,  it  is  quite  probable  that  all  the 
ram  water  would  be  saved  by  discharging  it  into  the  heater.  The 
elevator  as  shown  would  require  about  500  Ib.  of  water  per  trip,  or 
60,000  Ib.  per  day.  The  coal  which  the  elevator  would  handle 
would  evaporate  about  eight  times  as  much  water  as  would  be  used 
by  the  elevator. 

Unless  some  forethought  is  given  and  preparations  are  made  for 
sinking  the  cylinder  casings  considerable  trouble  may  be  expe- 
rienced. It  is  difficult  to  dig  a  small  deep  hole  and  even  more 
so  to  keep  it  plumb. 

The  most  usual  construction  is  to  drop  a  sheet  metal  sleeve  into 
a  hole  and  fill  in  around  it.  This  sleeve  should  be  considerably 
larger  than  the  cylinder. 

Care  must  be  taken  in  setting  the  sleeve  to  see  that  it  is  not  out 
of  place  more  than  the  clearance  between  it  and  the  cylinder.  This 
sheet  metal  sleeve  will  not  last  long  in  such  a  location,  and  to  prevent 
the  banks  from  closing  in  on  the  ram  cylinder  it  is  advisable  to 
fill  in  around  the  sleeve  with  a  sand  and  cement  grout  up  to  the 


HIGH  PRESSURE   WATER  PIPING. 


405 


point  where  the  concrete  floor  of  the  elevator  pit  begins.  If  the 
casing  leaks  so  badly  that  the  grout  runs  into  it,  the  interior  of  the 
sleeve  can  be  kept  from  filling  with  cement  by  filling  it  with  water. 
The  water  should  be  poured  in  so  that  its  level  is  about  the  same 
as  the  level  of  the  grout  around  the  exterior. 

Fig.  313  (01-3)  shows  a  hydraulic  lift  with  the  sleeve  in  place 
and  a  turntable  on  top  of  the  platform.     Ordinarily  the  pit  for  the 


FIG.  313  (Oi-3). 

platform  would  not  be  over  18  in.  deep.  A  catch  basin  should  be 
placed  at  the  bottom  of  the  pit  to  discharge  any  water  getting  into  it. 
The  bottom  end  of  the  ram  should  be  closed  air  tight,  for  if  it  is 
left  open  the  inside  of  the  ram  will  fill  with  air,  become  "air 
bound"  and  cause  the  elevator  to  bounce  up  and  down.  If  the 
air  is  discharged  at  the  top,  and  the  center  of  the  ram  is  filled  with 
water,  the  pressure  on  the  bottom  of  the  ram  will  be  reduced  by  an 


406 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


FIG.  314  (Oi-4). 


amount  equal  to  the  area  of  the  head  times  the  weight  of  a  column 
of  water  as  high  as  the  length  of  the  ram.  Two  guides  for  the 
platform  are  generally  fitted  at  diagonally  opposite  corners  of 
the  elevator  shaft.  This  is  necessary  if  a  turntable  is  used  on 
the  elevator  platform.  For  small  power  houses  this  type  of  the 
elevator  is  in  many  ways  better  than  a  high-speed 
electric  elevator,  being  less  easily  damaged  by 
careless  handling  and  less  liable  to  accident.  If 
the  lift  were  16  ft.  or  over  it  would  be  quite  an 
undertaking  to  sink  the  casing  plumb  for  such  a 
distance  and  in  such  cases  an  outside  cylinder 
with  overhead  sheaves  and  cable  would  be  simpler 
to  install  and  would  be  somewhat  less  expensive. 
Such  a  lift  is  shown  in  Fig.  314  (Oi~4),  the 
hydraulic  ram  in  this  case  having  one-half  the 
travel  of  the  elevator  platform.  A  sufficient 
counterweight  must  be  loaded  on  the  ram  to 
permit  it  to  discharge  the  water  and  raise  the  platform  when 
loaded.  This  construction  is  quite  similar  to  the  standard  high- 
lift  elevator  construction.  For  high  lifts  an  electrically 
operated  elevator  may  be  found  more  economical  to 
operate. 

It  is  only  for  a  low  lift  that  the  type  of  elevator  shown 
in  Fig.  313  is  particularly  adapted  in  power 
station  work.  An  operating  valve  and  oper- 
ating cable  are  shown  in  Fig.  315  (01-5). 
Automatic  stops  (top  and  bottom  limits)  are 
clamped  to  the  operating  cable,  which,  being 
struck  by  an  arm  extending  from  the  platform, 
automatically  shut  off  the  water  and  stop  the 
elevator  at  the  upper  and  lower  levels. 

The  pressure  pipe  for  such  an  installation 
should  be  carried  above  ground,  but  the 
waste  pipe  may  be  run  underground,  especially 
if  it  discharges  into  a  sewer.  Unfortunately  the  location  of  the 
operating  valve  is  generally  such  that  it  precludes  the  possibility 
of  using  pipe  bends  instead  of  elbows,  but  if  it  were  possible  to 
use  them,  the  hoist  would  operate  more  quickly  without  requiring 
any  greater  power  from  the  pump. 


CHAPTER    XXV. 


AIR    LINES. 

Class  PI  —  Air  Lines  —  Main.  The  use  of  compressed  air  in 
power  stations  is  quite  general,  but  for  some  classes  of  work  it  is 
used  because  it  is  available  rather  than  because  it  is  especially 
suitable.  Ordinarily  a  motor-driven  compressor  of  the  type  used 
on  electric  railway  cars  having  an  automatic  governor  is  used. 
Air  in  many  plants  is  used  for  blowing  out  dust  and  cleaning 
electrical  machinery.  These  requirements  are  sufficiently  urgent 
to  make  the  installation  of  a  compressor  necessary.  An  air  tank 
about  1 8  in.  in  diameter  and  5  ft.  high  should  be  used  to  provide 
for  sudden  demands  for  air  beyond  the  capacity  of  the  compressor. 
For  ordinary  station  use  a  steam-driven  air  compressor  will  be 
found  to  be  more  expensive  and  more  troublesome  to  operate  than 
the  regular  air  compressor. 

The  air  main  and  its  branches  may  be  made  of  black  iron  pipe 
'with  cast-iron  fittings.  The  heating  of  the  air  as  it  is  compressed 
is  not  sufficient  to  require  any  special  consideration  other  than  in 
the  compressor  itself.  For  stationary  service,  compressors  are 
usually  water  jacketed,  for  the 
reason  that  water  is  available 
and  can  be  circulated  without 
the  difficulties  to  be  met  with 
in  water  jacketing  a  com- 
pressor in  car  service.  If  a 
small  Compressor  with  a  water 
jacket  is  obtainable  it  should 
be  used.  To  avoid  the  neg- 
lect of  opening  the  jacket 
lines  when  the  compressor  is 
started  it  may  be  well  to  use  a  tank,  as  shown  in  Fig.  316  (Pi-i). 
Whenever  heat  is  delivered  to  the  cylinder  the  water  will  start  to 
circulate  and  keep  the  cylinder  cool  until  all  the  water  in  the  tank 
becomes  heated.  A  compressor  thus  fitted  will  show  less  wear  on  the 

407 


FIG.  316  (Pi-i). 


408  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

piston,  cylinder  and  valves  and  will  require  less  oil  for  internal 
lubrication.  The  motor  would  not  have  as  heavy  a  load  and  a 
greater  quantity  of  air  would  be  delivered  than  otherwise. 

Class  P2  —  Air  Lines  for  Blowing  Out  Electrical  Apparatus. 
The  earlier  method  of  blowing  dirt  out  of  electrical  windings  was 
by  use  of  hand  bellows,  but  as  the  size  of  electrical  apparatus 
increased  and  as  higher  voltages  were  used,  the  necessity  for  a 
more  efficient  air  supply  made  the  use  of  air  compressors  necessary. 
The  cleaning  of  the  electrical  machinery  is  not  merely  a  matter  of 
appearance,  but  it  is  absolutely  necessary  to  prevent  short  circuits. 
The  higher  the  air  pressure,  the  more  thoroughly  is  it  possible  to 
remove  the  dirt.  By  making  this  cleaning  operation  simple  and 
convenient,  the  attendant  takes  much  better  care  of  his  apparatus. 

The  air  pipe  lines  are  generally  i-in.  mains  and  J-in.  branches 
to  hose  valves.  It  is  good  practice  to  install  a  large  number  of  hose 
connections,  making  the  use  of  a  long  line  of  hose  unnecessary. 
The  hose  should  be  |  in.  in  size  with  a  small  opening  nozzle  provided 
with  a  valve.  The  hose  should  be  able  to  stand  60  Ib.  pressure. 
The  union  that  connects  with  the  hose  valves  should  have  two 
projecting  handles  so  that  the  hose  can  be  attached  and  detached 
without  a  wrench.  The  hose  connection  valves  should  be  f  in. 
with  a  hose  nipple  reduced  for  the  i-in.  hose.  Ordinarily  it  will 
be  necessary  to  have  hose  connections  at  each  generator,  converter, 
or  other  apparatus;  also  at  oil  switches,  back  of  the  switchboard 
and  other  places  where  dirt  and  dust  accumulate. 

Plants  that  use  air-cooled  transformers  should  be  provided 
against  picking  up  dust  through  the  fan  suction.  If  some  form  of 
a  vacuum  cleaner  could  be  used  on  floors  around  electrical  appara- 
tus, many  of  the  cleaning  troubles  would  be  solved. 

Class  P3  — Air  Lines  for  Oiling  Systems.  The  use  of  air  as 
applied  to  oiling  systems  is  shown  in  Figs.  56,  58  and  60.  The 
oiling  system  that  is  dependent  upon  air  for  its  operation  is  a  con- 
stant source  of  trouble,  as  it  is  then  necessary  to  have  an  air  pump 
always  in  service.  When  using  compressed  air  for  the  oiling 
system,  compressors  should  be  installed  that  are  adapted  to  con- 
tinuous operation.  The  use  of  both  air  and  oiling  systems  should 
be  considered  in  the  nature  of  conveniences  and  not  a  necessity. 
Nevertheless  one  frequently  finds  plants  operating  that  have  no 
other  means  of  supplying  oil  to  the  engine  than  by  an  oiling  system, 
.which  in  turn  depends  on  air  to  supply  the  necessary  pressure. 


AIR  LINES.  409 

Air  may  be  used  quite  successfully  to  raise  oil  from  a  receiving 
tank  to  a  gravity  tank,  but  to  do  this  requires  a  closed  tank,  which 
in  itself  is  an  objectionable  detail.  If  tanks  are  to  have  air  pressure 
upon  them,  they  should  be  arranged  as  shown  in  Fig.  317  (P3~i). 
Tank  No.  i  is  shown  ready  to  go  under  pressure  and  tank  No.  2 
ready  to  go  out  of  service.  The  position,  A,  is  that  of  the  valve 
previous  to  changing  over,  with  pressure  on  No.  2  and  No.  i  open 
to  the  atmosphere.  The  position,  B,  is  intermediate  with  all 
openings  closed.  Position,  C,  is  an  equalizing  position;  that  is, 
tanks  No.  i  and  No.  2  open  to  each  other.  This  position  is  retained 


FIG.  317  (?3-i).  FIG.  318  (P3-2). 

until  both  tanks  are  under  the  same  pressure.  Then  the  handle 
of  the  valve  is  moved  over  to  the  position  shown  as  D,  this  being 
with  pressure  on  No.  i,  and  No.  2  open  to  the  atmosphere.  Before 
changing  over  tanks,  it  will  be  necessary  to  close  drip  valve,  E;  also 
open  valve,  G.  Then,  when  the  air  valve  is  in  the  position  C, 
valve  H  can  be  closed  and  the  air  valve  then  thrown  over  to  posi- 
tion D.  As  soon  as  pressure  is  off  of  tank  No.  2,  the  tank  is  opened 
to  take  the  oil  drips. 

It  will  be  noted  that  by  having  separate  valves  E,  F,  G  and  H 
there  is  considerable  manipulation  required.  The  operation  of 
these  tanks  can  be  simplified  by  using  another  4-way  valve  con- 
nected to  the  same  handle  as  the  air  valve  shown  in  Fig.  317. 
The  handle  when  toward  either  single  tank  indicates  that  tank 
to  be  under  pressure  and  when  in  the  middle  position  as  equalized, 
there  being  but  three  positions  assumed  by  the  one  operating 
handle.  Fig.  318  (?3-2)  shows  the  position  of  the  oil  valve  when 
placed  in  unison  with  the  air  valve.  The  same  letters  in  Figs.  317 
and  318  show  a  like  position  of  the  handle.  Trie  small  port  cross- 
ing the  larger  one  may  be  obtained  by  drilling  through  the  plug 
valve  and  placing  a  tube  in  the  opening.  Ordinarily  a  small  port 
can  be  obtained  by  drilling  and  chipping,  as  shown  at  e  in  Fig.  318, 


4io 


STEAM  POWER  PLANT  PIPING   SYSTEMS. 


To  further  secure  the  oiling  system  against  trouble  in  case  the 
air  compressor  is  out  of  service,  also  to  avoid  fluctuating  pressure, 
it  will  be  necessary  to  use  an  air  storage  tank  and  check  valve  in 
the  supply  pipe. 

Class  P4  —  Air  Lines  for  Fire  Protection.  Rooms  containing 
inflammable  material,  such  as  benzine,  paints,  oils,  etc.,  can  best 

be  protected  with  an  air  blower  con- 
nected to  a  receptacle  holding  a  fire 
extinguishing  powder,  as  shown  in 
Fig.  319  (P4-i).  The  syphon  can 
be  an  ejector  tee  or  a  standard 
reduced  tee,  say  i  by  f  by  \  in. 
The  extinguishing  chemical  may  be 
either  dry  or  liquid.  The  amount 
discharged  can  be  controlled  by 
the  valve,  A.  The  chemical  ex- 
tinguisher is  especially  suited  for 
such  fires  as  flame  up,  as  oil,  paint, 
etc. 

Class  P5  —  Air  Lines  for  Signal  Whistles.  The  air  system  can 
often  be  used  very  satisfactorily  to  signal  from  engineer  to  switch- 
board operator,  as  the  air  lines  run  to  practically  all  the  machines 
and  is  easily  reached  for  whistle  branches.  There  should  be  a 
whistle  at  the  switchboard  so  that  the  operator  can  give  a  signal; 
also  a  whistle  at  the  engine  so  the  engineer  may  call  the  attention 
of  the  board  operator.  The  whistles  should  be  shrill  so  that  they 
can  be  heard  above  other  noises.  Whistle  signals  are  far-reaching 
and  can  be  used  more  effectively  than  a  bell  and  are  very  easily 
maintained.  Air  is  much  preferable  to  steam  for  all  whistles,  as 
air  whistles  can  be  located  anywhere,  are  free  from  water  and  are 
ready  to  blow  the  moment  the  whistle  valve  is  opened. 


FIG.  319  (P4-i)- 


CHAPTER   XXVI. 
STEAM    DRIPS. 

Class  Ql  —  Steam  Drips  from  Mains.  While  removing  the  con- 
densation from  pipe  lines  is  important,  it  is  not  this  that  causes 
so  much  destruction  to  engines,  but  the  water  carried  over  in  large 
quantities  with  the  steam  that  must  be  given  the  chief  consideration. 
Different  systems  for  removing  drips  from  pipe  lines  were  shown 
in  Figs.  36  to  44.  In  designing  a  drip  system  it  is  necessary  to 
consider  these  "slugs"  and  make  such  provision  as  will  protect 
the  machinery  from  damage. 

The  arrangement  shown    in  Fig.  320    (Qi-i)   is    satisfactory 
for  handling  condensation,  but  is  not  adapted  for  handling  large 
quantities  of  water.     The  header  as  shown  would  with  the  flow 
of  steam  drain  into  the  separator,  and  if  this  were  of  the  ordinary 
size  much  water  would  be  carried  through  to  the  engine.     A  safer 
plan  is  to  take  the  steam  from  the  top  of  the  header  and  place  the 
receiver  separator  at  the  engine  throttle.     The  header  would  then 
hold  back  a  large  quantity  of  this  water  and  discharge  it  through 
its  own  drip.     Further  to  insure  the  discharge  of  this  water  from 
the  header,  it  would  be  advisable  to  take 
the  steam  connection  for  the  reheater  coil 
from  the  bottom  of  the  header  and  allow 
any  water  to  work  its  way  through  the  coil 
to  the  drain.    This  is  a  very  desirable  way 
for   safeguarding    against    the    flooding   of 
engine    cylinders    because    the    velocity  of 
the  steam  passing  through  the  reheater  is 
high,  the  capacity  of  the  coil  is  large,  and 
there   is   no  mechanism  to  be  injured  by 
the  water.     As  the  heating  capacity  of  the        FIG.  320  (Qi-i). 
high  temperature  water  is  nearly  equal  to 
that  of  the  steam  there  will  be  but  little  difference  in  the  reheating 
temperature. 

Unfortunately  the  details  that  insure  engine  cylinders  against 

411 


412  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

flooding  increase  the  condensation  loss.  This  is  true  except  for 
those  steam  lines  that  may  be  taken  from  the  bottom  of  steam 
mains  and  feed  the  auxiliary  service  where  water  is  not  dangerous. 
Large  headers  or  separators  are  a  source  of  constant  radiation  loss, 
and  if  used  with  .superheated  steam  the  losses  from  radiation  in 
these  become  greater  than  the  loss  from  friction.  If  superheated 
steam  is  to  be  used  it  will  materially  affect  the  design  of  the  pipe 
work,  the  steam  supply  and  drip  system. 

No  one  feature  of  station  operation  causes  so  much  water  to 
be  carried  into  steam  lines  as  high  water  in  the  boilers.  As  soon 
as  engineers  realize  that  feed  regulators  do  more  than  save  trouble 
for  the  fireman,  they  will  use  them  as  they  would  a  damper 
regulator,  to  save  cost  of  operation,  and  then  the  ever-repeating 
difficulties  arising  from  high  and  low  water  will  almost  entirely 
be  eliminated.  Regulators  are  now  in  the  market  which  do  not 
require  floats  and  have  an  excess  of  power  available  to  handle 
feed  valves.  The  amount  of  attention  required  to  keep  them  in 
good  order  is  small  compared  with  the  labor  of  constantly  watch- 
ing the  water  level  and  regulating  the  feed  valves.  By  using  feed 
regulators  it  is  possible  to  carry  a  much  lower  water  level,  thus 
insuring  drier  steam  and  imposing  less  work  on  the  drip  line.  With 
a  uniformly  low  water  level  it  is  nearly  impossible  for  boilers  to 
throw  any  great  quantity  of  water.  Where  the  boiler  water  is 
bad,  carrying  the  water  level  low  considerably  reduces  .the  danger 
of  water  being  carried  over  into  the  steam  line. 

It  is  well  to  remember  that  superheat  will  remain  in  the  steam 
only  when  the  steam  is  handled  at  high  velocity — 6,000  to  10,000  ft. 
per  min.  If  the  steam  velocity  is  low,  even  with  a  superheat 
of  200  degrees,  all  or  part  of  this  will  be  lost  before  the  engine 
cylinder  is  reached.  This  condition  calls  for  special  consideration 
in  the  design  of  steam  lines,  as  follows: 

1.  The  steam  lines  should  be  as  short  as  possible. 

2.  The  size  of  the  pipe  should  be  small  to  reduce  the  radiation 
losses  so  that  they  will  be  approximately  the  same  as  frictional 
heat  losses. 

3.  The  line  from  the  boiler  to  the  engine  should  be  free  from 
abrupt  turns. 

4.  Such  portions  of  the  steam  lines  as  carry  steam  moving  at  a 
low  velocity,  should  be  provided  with  drip  connections. 

5.  Large  receivers,  separators,  etc.,  should  not  be  used. 


STEAM  DRIPS. 


413 


•"•    v^ 


Where  drip  connections  are  necessary,  the  best  method  is  to 
have  small  pockets  in  the  Y-fittings  and  take  the  steam  from  these 
pockets  to  a  drip  separator  and  from  the  drip  separator  to  the 
auxiliaries,  as  shown  in  Fig.  321  (Qi-2).  Ordinarily  Y-fittings 
are  objectionable,  but  as  they 
offer  much  less  resistance  to  steam 
flow  their  use  is  desirable  for 
superheated  steam.  The  boiler 
branches  should  have  long  bends 
and  no  elbows  because  the 
friction  of  one  5-in.,  po-degree 
elbow  is  about  the  same  as  that  of  /&w»  ^^\  •"• 
a  full  length  of  a  5-in.  pipe.  In  ^U^/f^ 
Fig.  321  it  will  be  noted  that  FlG  32I  (Ql_2> 

water  cannot  lie  in  the  end  of  a 

steam  main,  as  shown  at  A,  when  boilers  B  alone  are  in  operation, 
because  steam  is  flowing  to  the  auxiliaries  at  all  times. 

In  regular  operation  there  will  be  little  or  no  drip  to  care  for 
in  the  arrangement  shown  in  Fig.  321,  but  when  starting  a 
plant  with  no  steam  flowing  to  its  steam  machines  there  will  be  as 
much  drip  as  though  superheaters  were  not  used. 

Class  Q2  —  Steam  Drips  from  Separators.  Nearly  all  separators 
include  some  method  of  diverting  the  flow  of  the  steam  and  rely 
for  separation  upon  the  inertia  of  the  heavy  particles  to  cause  them 
to  leave  the  steam  at  the  point  where  flow  is  diverted.  This  form 
of  separator  is  shown  in  Fig.  322  (Q2-i)  as  No.  i  and  No.  2. 
The  area  of  discharge  is  maintained  practically  the  same  through 
the  separator  as  in  the  pipe  itself.  Another  method  for  obtaining 
like  result  is  to  decrease  the  flow  in  the  separator  and  allow  the 
condensation  to  drop  out,  as  shown  in  No.  3,  Fig.  322.  This 
requires  an  extremely  large  device.  A  very  efficient  separator  is 
one  in  which  the  principles  of  these  two  are  combined.  No.  4 
and  No.  5  show  different  types  embodying  this  idea.  No.  4  takes 
up  about  three  times  the  space  of  No.  5,  and  the  velocity  of  the 
steam  at  the  turn  is  one-third  greater.  The  area  of  the  steam 
passage  in  No.  5  is  14  times  the  area  of  the  pipe.  No.  5  has  the 
advantage  that  the  resistance  of  the  separator  is  immeasurable  on 
account  of  its  large  port  area.  The  steam  is  divided  into  thin 
films  as  it  makes  the  turn,  and  the  condensation  has  the  least 
possible  distance  to  travel  to  get  out  of  the  flow.  As  the  separator 


414 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


is  relatively  small  in  size,   it   can  be  very  easily  and  favorably 
located. 

In  laying  out  a  drip  system  some  method  should  be  provided 
so  that  this  pure  water  of  high  temperature  will  not  be  wasted  to 
the  sewer.  The  usual  method  of  discharging  this  condensation 


FIG.  322  (Q2-i). 


into  the  heater  is  not  generally  economical.  If  an  economizer 
is  used  it  will  be  best  to  discharge  the  drips  directly  into  the  boilers, 
as  was  shown  in  Fig.  36. 

Class  Q3  —  Steam  Drips  from  Boiler  and  Engine  Branches. 
Various  forms  of  boiler  branches  are  shown  —  Figs.  78  to  88. 
The  different  engine  branches  as  shown  in  Figs.  74  to  77  usually 
require  drains.  These  drains  can  nearly  always  be  connected 
with  the  sewer  and  should  be  closed  except  when  starting  up. 

Class  Q4  —  Steam  Drips  from  Auxiliary  Steam  Main  and 
Gravity  Return.  If  the  auxiliaries  are  placed  far  from  the  main 
steam  line  it  is  necessary  to  put  in  an  auxiliary  steam  main.  In 
some  installations  auxiliaries  are  operated  at  a  lower  pressure, 
making  use  of  a  reducing  valve  necessary.  A  usual  method  is  to 


STEAM  DRIPS. 


415 


locate  auxiliary  main  in  such  a  way  that  the  drips  from  the  main 
steam  header  will  flow  to  the  auxiliary  main  and  thus  work  through 
the  pumps  and  other  devices  where  water  can  do  no  particular 
harm.  Figs.  40,  41,  42  and  44  show  these  different  systems.  In 
Fig.  40  all  the  drips  are  shown  as  collected  in  a  drip  main  and 
delivered  to  an  elevated  receiver  or  separator,  which  discharges 
its  drip  back  to  the  boiler  and  by  gravity  and  the  steam  to  the 
auxiliary  steam  main.  Figs.  41 
and  42  show  a  large-sized  auxiliary 
main,  which  takes  the  steam  from 
the  various  drip  pockets  to  the 
steam  header.  The  auxiliaries 
take  their  steam  from  the  top  of 
the  auxiliary  main,  and  the  con- 
densation flows  into  an  automatic 
drip  receiver  and  pump,  which 
returns  the  drips  to  the  boilers. 
In  Fig.  44  an  overhead  receiver- 
separator  is  used.  Fig.  323  (Q4~i) 
shows  the  general  arrangement  of 
this  overhead  receiver-separator. 
The  connection  to  this  separator 
is  made  at  a  low  point  in  the  drip 
main  to  insure  regular  working 
conditions.  It  is  necessary  to 
take  a  small  amount  of  steam 
from  this  overhead  separator, 
which  may  be  used  for  a  heating 
system,  or,  if  economy  is  to  be 
disregarded,  may  be  discharged  to  the  atmosphere.  A  large  flow, 
however,  would  maintain  the  pressure  in  various  parts  of  the 
system  that  would  somewhat  simplify  operation. 

Where  there  are  numerous  drip  pockets  which  drain  into  a  com- 
mon drip  main  they  are  likely  to  be  of  different  heights,  producing 
different  pressures.  The  pockets  which  are  under  lower  pressure 
must  have  sufficient  head  in  the  drip  branch  so  that  the  weight 
of  the  column  of  condensation  will  exceed  this  pressure  difference, 
thus  insuring  a  discharge  even  with  the  lower  pressure  branches. 
For  instance,  the  reheating  coil  in  the  low-pressure  receiver  may 
have  five  pounds  less  pressure  at  its  drip  discharge  and  it  may  be 


FIG.  323  (Q4-i). 


416  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

located  within  a  foot  of  the  basement  floor;  there  are  two  means 
of  removing  such  drips,  the  simplest  being  to  pass  the  highest 
pressure  drips  through  the  coils  and  in  this  manner  make  them  all 
low-pressure  drips.  The  other  method  is  to  use  a  float-operated 
resistance  in  the  high-pressure  drip  pockets,  thus  causing  a 
decrease  in  pressure  in  the  drip  branch  as  soon  as  condensation  is 
discharged,  and  permitting  the  low-pressure  drips  to  discharge. 

Referring  to  Fig.  323  it  will  be  noted  that  a  trap  discharge  is 
provided  for  receiver-separator,  this  trap  operating  only  when 
the  water  in  the  receiver  rises  above  a  certain  level.  This  water 
line  can  rise,  when  all  boilers  are  shut  off  from  the  return  drip 
system  and  also  when  there  is  no  flow  of  steam  to  the  auxiliary 
main.  Whenever  the  riser  to  receiver-separator  fills  with  water 
the  weight  is  increased  until  it  becomes  heavier  than  the  column 
to  the  boiler;  then  the  water  ceases  to  return  to  the  boiler,  the 
steam  condenses  in  the  overhead  receiver,  the  water  level  rises 
and  discharges  water  from  the  trap.  No  water  passes  the  boiler 
check  valves  until  steam  again  flows  to  the  auxiliary  main. 

In  practice  there  is  always  a  feed  pump  running  and  this  alone  is 
sufficient  to  operate  the  drip  return  system.  The  amount  of  steam 
required  for  the  feed  pump  is  about  the  same  as  the  amount  of 
condensation.  Many  drip  return  systems  are  operated  by  allow- 
ing the  steam  to  waste  to  the  atmosphere  at  the  drip  receiver,  the 
amount  required  being  about  one-twentieth  of  i  per  .cent  of  the 
steam  generated.  In  practice  a  greater  loss  is  necessary  to  insure 
the  successful  handling  of  drips  when  the  boilers  are  throwing  over 
water.  It  is  to  insure  an  abundance  of  steam  to  raise  the  drips 
without  an  accompanying  loss  that  steam  from  the  drip  receiver 
is  delivered  to  some  piece  of  steam  apparatus  in  constant  opera- 
tion. Instead  of  using  the  trap  to  discharge  from  an  overhead 
receiver,  a  pressure  relief  valve  can  be  used,  opening  and  relieving 
the  steam  pressure  whenever  there  is  no  machinery  using  steam. 
This  type  of  drip  return  is  more  satisfactory  than  any  pump  return 
drip  system  and  is  being  extensively  employed. 

Class  Q5  —  Steam  Drips  from  Pump  Branches.  In  long  pump 
branches  the  considerable  condensation  makes  some  device  for 
removing  the  steam  from  the  water  absolutely  necessary.  For 
this  purpose  a  receiver-separator  is  often  located  at  the  pump 
close  to  the  throttle  valve.  By  connecting  this  receiver  to  the  drip 
system,  or  by  using  a  hand-operated  bleeder,  it  is  possible  to  get 


STEAM   DRIPS. 


417 


dry  steam  for  the  pump,  even  if  the  distance  from  the  steam  main 
is  great. 

The  use  of  a  receiver-separator  is  advisable  for  all  classes  of 
steam  machines  that  are  located  at  the  end  of  long  steam  lines, 
the  principal  advantages  being  better  lubrication  and  a  drier 
steam.  Where  the  steam  machines  are  comparatively  small  and 
placed  close  together  it  will  be  much  better  to  run  a  steam  line 
from  machine  to  machine  than  to  put  in  an  auxiliary  main  with 
branches.  By  taking  steam  from  the  top  of  the  pipe  and  slightly 
sloping  the  pipe  and  placing  a  drip  receiver  at  the  lower  end,  dry 
steam  for  the  auxiliaries  will  be  insured. 

Class    Q6  —  Drips    from   Pump  Steam    Cylinders.     The    drips 
from  pump  steam  cylinders  are  present,  even  though  the  steam 
branch  to  the  pump  be  well  drained  or  free  from  condensation. 
Such  cylinder  drains  are  often  the  only  means  of  discharging  the 
condensation  from  the  branch  line.     The  best 
arrangement  that  can  be  provided  for  pump 
cylinder  drains  is  shown  in  Fig.  324  (Q6-i). 
The  operation  of  but  one  valve  is  required  to 
open  the  four  drains  of  the  duplex  pump.     An 
arrangement  of   check  valves  prevents  water       FIG.  324  (Q6-i). 
being  blown  back  into  the  cylinder  which  is 
exhausting  to  the  atmosphere.     If  the  steam  to  the  pump  is  fairly 
free  from  moisture  these  drains  are  closed  while  the  pump  is  in  oper- 
ation, and  for  the  short  time  they  are  open  in  starting  no  difficulty 
will  be  encountered  in  discharging  to  an  open  drain. 

Class  Q7  —  Steam  Drips  from  Engine  Cylinders  and  Reliefs. 
All  engines  require  cylinder  drains,  either  as  a  part  of  the  engine 
or  pipe  separator.  With  Corliss  engines,  having  a  release  device 
at  the  eccentric  rods,  drips  can  be  discharged  first  from  steam 
branch  to  cylinder,  then  from  cylinder  to  exhaust  by  moving  the 
valves  by  hand.  Engines  that  are  not  equipped  with  the  releasing 
gear  require  drips  to  free  them  from  condensation  when  starting  up. 
Pipe  drips  should  have  valves  worked  by  hand,  and  to  provide 
against  water  while  the  engine  is  running  it  is  customary  to 
connect  at  each  end  of  a  cylinder  an  automatic  relief  valve  set 
at  a  pressure  slightly  higher  than  the  steam  pressure.  On  a 
Corliss  type  of  engine  it  is  customary  to  place  the  relief  valve 
horizontally  and  above  the  cap  of  the  exhaust  valve,  as  shown  in 
Fig.  157- 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


Class  Q8  —  Steam  Drips  from  Engine  Receiver  and  Reheater. 

In  an  installation  having  compound  engines,  reheating  receiver, 
steam  separator,  condenser,  etc.,  as  shown  in  Fig.  325  (Q7~i), 
there  would  be  a  large  amount  of  drips.  This  figure  also  shows  the 
cylinder  drip  connections  which  would  be  used  in  case  a  release 
device  on  the  valve  gear  were  not  provided.  The  by-pass  from 


FIG.  325  (Q7-i). 

steam  separator  and  drip  line  would  be  used  only  in  an  emergency 
when  the  reheating  coil  was  out  of  service  or  when  the  drain  would 
not  pass  the  water  fast  enough.  In  case  of  high  water  or  bad 
water  the  use  of  this  waste  would  be  necessary  to  prevent  injury 
to  the  engine. . 

The  object  in  passing  all  drips  through  the  reheater  coil  is,  as 
previously  noted,  to  -insure  quick  removal  and  to  eliminate  hand- 
ling drips  of  different  pressures.  The  warming  pipe  is  used 
before  starting  up  and  should  be  installed  regardless  of  whether  the 
valves  can  be  hand  operated  or  not,  as  it  allows  steam  to  be  put 
on  both  sides  of  the  piston.  By  the  use  of  these  warming  pipes 
the  different  parts  of  the  engine  may  be  heated  and  expand  to  their 
normal  size  and  form  before  moving  over  the  wearing  surfaces. 
It  is  well  known  that  a  perfect,  dense  and  glossy  surface  is  secured 
in  the  cylinder,  on  the  piston  and  valves  only  after  considerable 
time  and  care  have  been  expended  to  secure  it.  These  surfaces 


STEAM  DRIPS.  419 

can  easily  be  destroyed  by  moving  one  part  over  another  when 
they  are  not  at  their  normal  running  temperature,  in  which  case, 
instead  of  the  pressure  being  low,  it  is  sufficiently  high  to  preclude 
the  possibility  of  oil  reaching  the  sliding  surfaces.  When  an 
engine  groans  in  starting  up,  it  is  unmistakable  evidence  that  the 
smooth  surface  gained  by  normal  operation  is  being  injured. 

The  starting  drain  at  the  top  of  the  throttle  is  not  a  universal 
detail,  as  it  is  possible  to  pass  this  condensation  through  the  engine 
by  opening  the  throttle.  By  the  use  of  the  starting  drain  the  oil 
is  not  so  completely  washed  out  of  the  cylinder.  The  cylinder 
drains  should  be  piped  to  one  side  so  that  an  extension  valve  stem 
and  hand  wheel  placed  above  the  floor  can  be  used.  Special 
care  must  be  observed  in  running  cylinder  drips  to  avoid  the  pos- 
sibility of  water  being  drawn  back  into  the  cylinders  when  under 
a  partial  vacuum,  as  will  be  the  case  when  the  engine  is  being 
started  and  the  little  steam  admitted  expands  below  atmospheric 
pressure.  Ordinarily  each  drain  is  run  separately  to  the  exhaust. 
The  safety  of  this  arrangement  is  contingent  upon  the  certainty 
of  the  exhaust  being  free  from  water.  The  arrangement  recom- 
mended by  the  engine  builders  is  to  run  each  drain  separately 
to  a  catch  basin  in  the  basement  floor,  with  the  end  of  the  drip 
pipe  above  the  floor  level,  so  that  it  is  impossible  to  draw  water 
back  into  it.  In  no  case  should  the  drain  from  one  end  of  the 
cylinder  be  connected  with  the  drain  from  the  other  end;  each 
drain  should  be  separately  piped  to  the  point  of  discharge,  so  that 
when  one  pipe  is  discharging  water  and  the  other  one  sucking  air 
there  will  be  no  danger  of  water  being  drawn  back  into  the  cylinder. 
Where  escaping  steam  is  objectionable  a  drip  tank  can  be  used, 
but  it  should  always  be  open  to  the  atmosphere  and  to  the  sewer. 

Class  Q9 — Drips  from  Steam  Loop.  In  Fig.  326  (Qp-i) 
condensation  is  being  taken  by  the  gravity  return  loop  from  an 
elevation  lower  than  the  boiler  into  which  it  is  discharged.  To 
maintain  this  system  in  operation  it  is  necessary  that  the  weight 
of  the  column,  A,  shall  be  less  than  the  weight  of  column  B. 
The  riser  leg,  A,  will  contain,  when  working,  water  at  a  tempera- 
ture of  the  steam  —  say,  140  Ib.  pressure  —  which  will  make 
the  weight  of  the  water  55.16  Ib.  per  cu.  ft.  The  drop  leg  must 
be  sufficiently  exposed  to  lower  the  temperature  of  the  water 
100  degrees,  say,  to  250  degrees.  At  this  temperature  the  water 
would  weigh  58.81  Ib.  per  cu.  ft.  With  these  temperatures,  if 


420 


STEAM  POWER   PLANT  PIPING  SYSTEMS. 


riser,  A,  were  50  ft.  and  distance,  C,  one  foot,  B  plus  C  would 
have  to  be  47  ft.  and  distance,  D,  3  ft.  to  make  the  system  operative 
when  full  of  water.  This,  however,  is  not  the  usual  method  of 
operation.  The  distance,  D,  is  generally  15  or  20  ft.  In  order 
to  maintain  water  in  the  leg,  B,  continuously  heavier  than  leg,  A , 
it  will  be  necessary  that  the  contents  of  leg,  A,  be  steam  and  water, 
the  steam  flowing  at  sufficient  velocity  to  carry  the  condensation 


FIG.  326  (Q9-i). 

upward  and  into  the  condensation  pipe.  The  riser,  A,  must  be 
sufficiently  small  to  produce  this  velocity  and  the  condenser  pipe 
sufficiently  large  to  condense  the  steam  that  passes  through  riser,  A . 
The  difference  in  water,  temperatures  of  the  two  legs  is  quite  a 
negligible  quantity,  the  system  being  operative  with  water  and 
drip  legs  practically  at  the  same  temperature  as  the  steam. 

There  are  many  features  to  be  considered  in  connection  with  this 
type  of  drip  return  which  require  extra  judgment  to  determine. 
With  a  small  size  of  riser  pipe  a  greater  pressure  drop  is  necessary, 
and  to  permit  this  greater  pressure  drop  the  drop  leg,  B,  must  be 


'  STEAM   DRIPS.  421 

increased  accordingly.  If  riser,  A,  is  made  very  large,  then  the 
riser,  B,  can  be  short,  but  the  condenser  pipe  must  be  increased 
to  condense  the  increased  amount  of  steam.  If  the  system  is 
laid  out  in  a  comprehensive  manner  to  do  certain  work,  it  is  pos- 
sible to  operate  this  loop  very  satisfactorily.  The  valve,  £, 
controls  the  flow  through  the  loop  and  is  set  by  observing  the 
water  level  in  the  gage  glass  at  the  top  of  the  drop  leg.  The 
closing  of  the  valve,  E,  decreases  the  pressure  accordingly  for  the 
entire  loop,  and  the  water  in  the  gage  glass  rises  until  its  head 
equals  all  the  losses. 

In  comparing  this  drip  system  with  that  shown  in  Fig.  323  it 
will  be  noted  that  the  two  systems  are  very  similar  in  that  they 
both  carry  condensation  to  an  elevation  so  that  it  will  flow  to  the 
boiler  —  one  condensing  steam  to  effect  this  result,  the  other 
using  the  steam.  The  system  shown  in  Fig.  326  could  go  out 
of  service  without  any  ready  means  of  showing  it;  but  the  system 
in  Fig.  323  would  show  quite  plainly  by  the  water  passing  through 
the  feed  pump. 

Class  Q10  —  Steam  Drips  from  Automatic  Pump.  In  the  best 
station  practice  moving  parts  are  eliminated  wherever  it  is  possible 
to  obtain  desirable  results  in  other  ways.  The  automatic  drip 
pump  generally  possesses  some  detail  that  requires  considerable 
attention.  If  the  float  is  air  tight  and  sealed,  it  is  liable  to 
become  water  logged  or  collapse.  If  it  is  an  open  bucket  with 
a  counterbalance,  it  is  liable  to 
become  filled  with  mud  and  cease 
to  operate.  The  open  bucket  is  the 
most  reliable,  and  to  overcome 
the  difficulties  arising  from  the 
collection  of  mud  a  blow-ofT  should 
be  attached  to  clean  out  both  the 
receiver  and  the  bucket,  as  shown 
in  Fig.  327  (Qio-i).  The  register  Fic.  327  (Qio-i). 

type    of    balance    valve     is    often 

used  on  a  pump  for  this  service,  an  automatic  lubricator  being 
placed  above  the  throttle  to  lubricate  the  sliding  parts. 

The  work  for  an  automatic  pump  is  much  like  a  low-pressure 
service.  The  difference  in  pressure  is  very  slight,  but  the  pressure 
to  which  the  pump  may  sometimes  be  subjected  is  three  or  four 
times  the  boiler  pressure.  For  this  work  the  outside-packed 


422 


STEAM  POWER  PLANT  PIPING   SYSTEMS. 


plunger  pump  is  objectionable  for  two  distinct  reasons,  one  being 
that  the  plunger  packing  is  difficult  to  maintain  for  high  tempera- 
tures, and  the  other  that  plungers  must  be  packed  to  stand  high 
pressure,  while  the  pump  is  only  doing  low-pressure  service.  In 
the  latter  event  the  power  required  to  move  the  plunger  in  the 
packing  is  much  greater  than  the  power  required  to  pump  the  water. 
The  pump  shown  in  Fig.  277  is  suited  for  this  service,  as  it  has 
a  i-piece  brass  lining  in  place  of  the  packing  and  gland,  the  slight 
loss  by  slippage  being  much  less  than  the  frictional  loss  in  a  packed 
piston.  In  the  pump  shown  water  can  flow  from  the  reservoir 
into  the  cylinder  without  lowering  the  pressure  on  opening  the 
suction  valves.  The  lowering  of  pressure  on  high  temperature 
water  is  accompanied  by  re-evaporation,  causing  the  pump  to 
become  steam  bound,  and  unless  the  valves  are  mechanically 
operated  the  receiver  should  be  placed  not  less  than  18  to  24  in. 
above  the  pump. 

Class  Qll  —  Steam    Drips  from   Exhaust  Main  and   Branches. 
The  collection  of  drips  from  the  exhaust  main  is  a  low-pressure 
service,  and,  unless  the  cost  of  water  is  excessive 
and  an  oil  separator  used,  it  is  desirable  to  let 
them   go   to    waste.     Exhaust    mains    under 
atmospheric  pressure  are  quite  readily  drained 
by  a  U-shaped  water  seal,  as  shown  in  Figs. 
161  and  162.     A  very  simple  drain  trap  can 
be  used  for  this  service,  consisting  of  a  buoyant 
exhaust  valve,  as  shown  in  Fig.  328  (Qn-i). 
The  water  fills  the  trap  body,  and  the  partial 
vacuum  causes  the  valve  to  rise  to  the  surface 
of  the  water  and  return  to  its  seat  when  the 
water  is  discharged.     This  trap  is  operative 
under  a  more  limited  range  than  that  shown 
in  Figs.    161    and    162.     When   possible    the 
branches  and  main  should  be  laid  out  so  the 
drips  will  be  delivered  to  one  point. 
Class  Q12  —  Steam  Drips  from  Vacuum  Separator  and  Steam 
Traps.   The  ordinary  form  of  grease  extractor  is  shown  in  Fig.  154. 
The  drips  from  a  vacuum  line  require  a  special  trap  or  entrainer, 
which  part  of  the  time  may  be  under  the  same  pressure  as  the 
vacuum  line,  then  again  under  sufficient  pressure  to  ^charge 
against  the  atmosphere.     This  is  accomplished  by  having  a  steam 


FIG.  328  (Qn-i). 


STEAM   DRIPS. 


423 


line  running  to  trap  and  valves  in  both  the  drip  line  and  s^eam 
line,  one  of  which  is  closed  when  the  other  is  open,  a  float  device 
being  used  to  operate  the  valves.  Fig.  329  (Qi2-i)  shows  one 
form  of  the  device  in  which  the  steam  line  is  closed  when  the  drain 
is  open.  When  the  float  rises  the  line  to  the  vacuum  drip  is  closed 
and  the  steam  valve  is  open,  forcing  the  water  in  the  trap  through 
the  spring-closed  discharge.  In  some  types  the  float  operates 


ttiamtme 

FIG.  329  (Qi2-i). 


FIG.  330  (Qi2-2>. 


a  pilot  valve  which  admits  pressure  to  and  operates  a  multiported 
piston,  there  being  but  two  working  combinations  of  port  openings. 
The  pilot  valve  control  is  very  successfully  used  for  steam  traps 
of  the  type  shown  in  Fig.  330  (Qi2-2).  A  very  small  float,  with 
but  a  fraction  of  an  inch  travel,  will  control  a  large  discharge  valve. 

Two  steam  traps  of  the  same  resistance  are  able  to  discharge 
the  same  quantity  of  water  against  the  same  head.  The  capacity 
of  a  steam  trap  can  be  intelligently  stated  by  giving  its  head  loss 
when  discharging  a  given  quantity  of  water.  The  size  of  pipe 
connections  have  little  bearing  on  the  capacity  of  a  trap.  The 
head  loss  should  be  the  loss  in  pressure  as  measured  at  the  inlet 
and  the  outlet  pipes  close  to  the  traps,  being  the  loss  occasioned 
by  resistance.  In  specifying  for  a  trap  it  should  be  stated  that  the 
trap  shall  have  not  less  than  a  given  number  of  gallons  capacity, 
with  a  loss  of  pressure  not  to  exceed  a  certain  number  of  pounds, 
when  passing  through  the  trap. 

Class  Q13  —  Steam  Drips  from  Outside  Buildings.  This  service 
is  in  nearly  every  case  of  a  complex  nature.  The  collection  of 
drips  from  different  parts  of  the  various  buildings  invariably  offers 
many  obstacles  to  systematic  or  reliable  arrangement.  Some 


424  STEAM  POWER   PLANT  PIPING   SYSTEMS. 

drains  may  be  delivered  at  high  elevation,  others  at  a  lower  one. 
The  pressure  may  be  high  at  times,  and  at  other  times  very  low. 
A  system  for  this  purpose  must  be  able  to  take  drips  at  any  tem- 
perature, elevation  or  pressure  and  in  almost  any  quantity. 

Steam  lines  can  be  carried  long  distances,  first  to  a  high  elevation, 
then  to  a  lower  one,  and  then  up,  and  so  on,  without  any  other 
limitation  than  to  care  for  the  expansion  and  the  drips.  The 
high-pressure  line  can  generally  be  drained  by  steam  traps  at 
the  different  low  points,  delivering  into  a  special  drip  main,  the 
pressure  being  sufficient  to  return  the  drips  to  the  boiler  room. 
In  places  that  have  drips  of  a  lower  pressure  an  automatic  receiver 
pump  would  be  used.  Such  buildings  or  points  having  drips  of  a 
pressure  higher  than  the  drip  main  would  require  steam  traps  to 
discharge  drips  into  the  drip  main. 

When  the  pressure  of  the  drip  main  is  higher  than  that  of  the 
line  drained  a  pump  must  be  used.  These  limitations  must  be 
observed  in  all  the  drains  provided;  that  is,  the  drips  cannot  be 
handled  if  below  the  drip  main  pressure.  Another  difficulty  is 
in  the  maintenance  of  a  constant  drip  main  pressure.  This  is 
necessary  if  return  drip  pumps  are  used,  and  the  pressure  can 
generally  be  maintained  by  using  a  relief  valve  set  at  some  desired 
pressure  and  allow  drips  to  pass  from  the  drip  main  through  this 
relief  valve. 

When  drips  are  returned  from  many  points  in  large  quantities 
it  is  customary  to  use  a  drip  storage  tank,  and  feed  the  water  to 
the  boilers.  A  plant  having  many  mains  and  a  great  variety  of 
steam  condensing  devices  can  reduce  radiation  loss  and  insure 
better  results  in  general  by  using  boiler  feed  regulators  that  will 
increase  feed  to  boilers  at  the  same  time  the  quantity  of  returning 
drips  is  increased.  There  are  so  many  governing  features  in 
drip  returns  that  each  separate  feature  must  be  considered.  The 
following  points  must  be  considered  and  each  condition  safe- 
guarded. 

1.  The   drips   have   approximately   the   same   temperature   as 
the  steam,  and  on  discharging  into  a  lower  pressure,  much  steam 
is  formed. 

2.  Steam  traps  invariably  discharge  some  steam  before  they 
close. 

3.  Water  moving  in  "slugs"  separated  by  steam  will  strike  the 
fittings  much  the  same  as  if  it  were  a  solid  bar. 


STEAM   DRIPS.  42$ 

4.  The  velocity   that  water  will   travel  and   strike  fittings   is 
governed  more  by  the  rapidity  of  steam  condensing  in  the  drip 
lines  than  the  normal  flow  of  the  drips. 

5.  High  velocity  drips  prevent  water  and  steam  separating  into 
large  volumes  of  each,  the  entire  mass  being  broken  up  and  water 
hammer  practically  eliminated. 

6.  The  lower  the  drip  line  pressure  the  greater  will  be  the 
volume  of  vapor. 

7.  To  carry  a  partial  vacuum  on  drip  lines  serves  to  lower  the 
temperature,  the  action  of  water,  steam  and  air  in  the  lines  being 
the  same  as  at  any  other  pressure. 

8.  The  less  the  pressure  difference  between  a  drip  main  and 
that  drained,  the  less  will  be  the  difficulties  from  water  hammer. 

9.  Drips  can  be  carried  to  a  high  elevation  with  very  slight 
head  loss,  the  steam  and  water  being  intermingled  in  the  riser 
pipe. 

10.  Whenever  possible  the  steam  pressure  should  be  reduced 
so  that  the  drips  are  but  slightly  greater  in  pressure  than  the  drip 
main. 

11.  The  discharge  from  an  automatic  pump  must  be  of  higher 
pressure  than  its  suction. 

12.  The  high  condenser  pipe  of  a  steam  return  loop  must  have 
its  air  removed  with  a  vacuum  pump  if  its  pressure  be  below 
atmosphere. 

In  laying  out  a  system  the  drip  line  can  vary  in  elevation  if  at 
all  times  there  is  sufficient  steam  carried  to  sufficiently  reduce 
the  weight  of  the  total  mass.  Fig.  331  (Qi3-i)  shows  a  drip 
return  with  two  risers,  the  difference  in  the  pressure  at  the  two 
ends  being  slight  and  depending  upon  the  ability  of  the  horizontal 
lines  to  condense  the  steam.  The  vaporizer  delivers  steam  only 
when  an  insufficient  amount  is  passing  through  with  the  drips. 
The  efficiency  of  this  device  is  greater  than  that  of  the  steam  loop 
shown  in  Fig.  326,  as  it  rarely  uses  live  steam,  while  the  loop 
requires  live  steam  at  all  times.  When  water  rises  in  the  vaporizer 
live  steam  is  added,  but  as  long  as  water  is  carried  up  from  the 
riser  with  the  steam,  no  live  steam  is  necessary.  If  the  drip 
system  is  delivering  at  about  atmospheric  pressure,  one  cubic 
foot  of  water  will  make  about  1,600  cu.  ft.  of  steam.  If  the  total 
height  of  risers,  C,  D  and  £,  is  50  ft.  and  the  drop  leg,  F,  is  20  ft., 
then  30  ft.  of  the  50  ft.  in  the  riser  must  be  steam  and  not  require 


426 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


additional  head  to  carry  the  water  up  the  riser.  Ordinarily, 
much  more  than  one-half  the  volume  of  the  drip  is  steam,  and  live 
steam  will  not  be  required  to  lighten  the  riser  columns.  If  live 
steam  were  required  it  would  take  but  one  pound  of  boiler  water 
generated  into  steam  to  lighten  1,000  Ib.  of  drip  return  water. 

The  riser  should  be  sufficiently  small  to  insure  high  velocity, 
and  to  suit  variable  conditions  risers  may  be  in  pairs,  each  pair 

being  of  two  sizes  of  pipe, 
say  f-in.  and  i-in.,  which 
will  permit  either  being 
used  separately  or  both  in 
unison,  giving  capacity  in 
the  proportion  of  9  to  16 
to  25.  If  the  drip  system 
shown  in  Fig.  33 1  is  used 
to  remove  drips  from  pres- 
sure steam  mains,  these 
drips  can  be  returned 
against  boiler  pressure  even 
if  the  drips  are  at  10  Ib. 
below  the  boiler  pressure, 
in  which  event,  however,  it 
FIG-  331  (Qi3-i).  will  be  necessary  that  suffi- 

cient length  of  drop  leg  be 

used  to  overcome  this  difference  in  pressure.  If  the  drips  are  solid 
water  it  will  be  necessary  to  use  the  vaporizer  shown  in  Fig.  331 
to  raise  them  to  the  high  horizontal  condenser  pipe. 

The  greatest  objection  to  the  loop  drip  system  is  that  the  prin- 
ciple governing  its  operation  is  not  well  understood  by  those  who 
usually  have  it  in  charge. 

A  simpler  form,  although  possessing  more  parts,  is  that  shown 
in  Fig.  332  (Qi3~2).  On  the  score  of  simplicity  it  is  largely 
used  in  collecting  drips  from  surrounding  buildings.  Each 
building  has  a  drip  tank  provided  with  a  vaporizer  pipe.  The 
water  flows  by  gravity  from  these  tanks  to  the  main  station.  Such 
buildings  as  A,  which  have  tanks  located  at  a  high  elevation,  may 
have  a  low  level  tank  to  catch  all  the  building  drains  and  a  pump 
to  raise  these  drips  to  an  overhead  tank.  This  would  be  strictly 
a  gravity  system,  and  if  grease  were  removed  from  the  exhaust 
drips  they  could  be  returned  in  this  way.  Another  method  is  to 


STEAM   DRIPS. 


42; 


use  the  drip  tanks,  as  shown  in  Fig.  332,  with  each  tank  located  to 
suit  the  requirements.  In  a  small  float-controlled  pump  the  dis- 
charge from  the  different  buildings  is  taken  from  a  low-pressure 
main  to  an  elevated  tank  in  the  power  house,  then  to  an  open 
heater.  The  drip  mains  from  building  to  building  can  be  placed 
on  different  elevations,  since  the  entire  system  is  one  of  pressure 


FIG.  332  (Qi3-2). 

return.  The  boiler  room  tank  is  of  necessity  higher  than  any  of 
the  drip  lines.  This  system  as  well  as  that  shown  in  Fig.  332 
would  be  free  from  water  hammer  and  other  difficulties  arising 
from  steam  and  water  in  drip  lines.  To  avoid  trouble  from 
steam  in  drip  pipes,  it  would  be  advisable  to  discharge  traps,  etc., 
into  a  large  standpipe  vented  through  the  roof.  This  will  give 
storage  for  trap  discharge  and  at  the  same  time  permit  vapois 
to  escape  or  condense.  The  standpipe  should  have  about  twice  the 
diameter  of  the  trap  discharge.  The  method  shown  in  Fig.  331 
is  good,  and  modifications  can  be  made  that  will  permit  its  use 
in  many  places. 

If  live  steam  lines,  water  lines  and  electric  wires  also  run  be- 
tween buildings,  then  some  form  of  tunnel  will  be  advisable.    The 
pipe  lines  should  be  located  over  each 
other  and  at  one  side,  while  the  wires 
should  be  placed  at  the  top.     If  the 
expense  of  such  a  tunnel  bars  its  use, 
the  next  best  plan  is  to  use  a  masonry 
trench,  the  sides  and  bottom  having 
a  cover  that  is  a  slow  conductor  of 
heat    and    waterproof.      A    concrete  FIG.  333  (Qi3~3)- 

trench  with  a  wooden  top  is  shown 

in  Fig.  333  (Qi3~3).  A  top  having  single  boards  is  a  poor 
construction.  With  heat  on  one  side,  and  the  outside  exposed  to 
the  rain  and  sun,  the  boards  soon  warp  so  that  they  will  leak  air 


428  STEA^f  PO\YER  PLAXT  PIPING  SYSTEMS. 

and  water,  damaging  the  pipe  covering.  Each  cover  section 
should  be  one  sheet  of  galvanized  iron  with  the  ends  lapped  to 
protect  the  joints.  The  excelsior  filling  improves  the  insulating 
properties,  but  this  type  of  trench  cover  being  double  thickness 
with  an  air  space  makes  a  good  non-conductor  without  the  filling. 

Class  Q14  —  Steam  Drips  Miscellaneous.  The  safety  valve 
should  have  a  drain  to  discharge  such  condensation  as  may  be 
caused  by  steam  leakage  past  the  valve,  this  detail  being  shown 
in  Figs.  128  and  129.  The  drains  from  the  heating  system  are 
shown  in  Figs.  178,  179  and  180.  Drains  from  surface  conden- 
sers are  shown  in  Figs.  226  and  228.  The  drip  main  returning 
drips  to  boilers  is  shown  in  Figs.  36,  37,  40,  41  and  44.  The  drips 
should  not  in  any  case  be  discharged  into  the  feed  main.  High 
temperature  drips  have  more  or  less  vapor  or  steam  carried  in 
them  and  only  when  conditions  are  regularly  maintained  can  these 
high  temperature  drips  be.  delivered  to  a  feed  main  without  causing 
serious  water  hammer.  The  branches  from  drip  mains  to  boiler 
should  have  stop  valves  next  to  the  boiler,  a  check  valve  and 
another  stop  valve  next  to  the  drip  main. 

It  is  quite  safe  to  state  that  in  nearly  every  case  it  is  a  saving  to 
return  drips  to  the  boiler  in  some  manner.  If  but  i  per  cent  of  the 
steam  generated  in  a  i,ooo-hp.  plant  is  discharged  in  drips  then 
$360  can  be  invested  to  save  the  heat  units  and  show  10  per  cent  on 
the  investment.  The  value  of  returning  pure  water  is  in  many 
cases  even  greater  than  the  gain  in  saving  heat  units. 


CHAPTER    XXVII. 


OIL    PIPING. 

Class  Rl  —  Oil  and  Drip  Mains.  There  are  three  classes  of  oil 
mains  to  provide  for:  engine  oil  supply,  cylinder  oil  supply  and 
oil  drip  mains.  The  engine  oil  mains,  continually  under  pressure, 
are  used  in  connection  with  a  drip  return  system.  The  oil  pass- 
ing through  will  be  free  flowing,  and  the  cooler  this  oil  can  be 
kept  the  more  suitable  it  is  for  reducing  friction  and  the  tempera- 
ture of  engine  bearings.  In  making  up  the  joints  for  the  oiling 
system,  a  thread  filler  should  not  be  used.  The  most  perfect 
joints  are  made  by  using  clean  oil  and  clean  threads  on  iron  pipe, 
the  fittings  being  of  rough  brass.  The  use  of  brass  pipe  should  be 
avoided,  as  it  increases  the  cost  of  installation,  and  all  brass  joints 
are  difficult  to  make  tight.  Galvanized  pipe  is  suitable,  as  this 
pipe  must  be  of  a  good  grade  to  be  galvanized,  and  in  the  process 
the  pipe  is  pickled,  which  removes  most  of  its  scale.  Malleable 
iron  fittings  should  not  be  used,  as  they  are  not  stiff  enough  ordi- 
narily to  make  up  oil-tight  joints.  Heavy  cast-iron  fittings  and 
galvanized  pipe  or  drawn  steel  tubing  and  brass  fittings  make 
the  best  combinations. 

The  joint  shown  in  Fig.  334  (Ri-i)  permits  the  pipe  being 
screwed  up  to  the  shoulder.  The  round  joint  nuts  or  rings  of 
steel  are  screwed  up  when  the  pipes 
are  all  in  place;  this  compresses  the 
brass  fitting,  making  the  joint  tight. 
A  strong  connection  results,  offering 
a  smooth  bore,  free  from  shoulders 
and  projections  that  collect  sediment 
and  block  the  pipe.  The  valves 
should  be  smooth-bore  cocks,  with 
ends  "made  up  the  same  as  the  fitting 

shown.     The   inside  of  the  pipe  should  have  its  ends  reamed 
concentric  with  the  fittings.     A  sediment  pocket  with  a  plug  at 


FIG.  334  (Ri-i). 


its  bottom  for  cleaning  should  be  provided. 

429 


Crosses  are  often 


43 O  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

used   for   this   purpose,   but  are  objectionable,   as   the   pockets 
are  small. 

The  drip  mains  are  the  main  sewer,  with  no  head,  and  running 
part  full,  carrying  all  the  impurities  washed  into  them.  Much 
trouble  is  experienced  with  these  drip  lines  if  made  with  standard 
pipe  and  fittings.  The  details  essential  for  sewer  connections 
are  clearly  shown  for  the  drip  main: 

1.  The  bottom  of   the  drain   must   be   a   smooth,   unbroken 
surface  free  from  pockets  or  projections. 

2.  In  case  it  is  necessary  to  make  a  drop,  means  should  be 
provided  for  cleaning  out  the  trap  thus  formed. 

3.  A  gradual  fall  should  be  given  the  line. 

4.  A  means  for  cleaning  the  line  should  be  available. 

If  the  length  of  the  drip  main  is  not  more  than  one  length  of 
pipe,  then  a  large  pipe  of,,  say,  2-J-  in.  can  be  used.     The  drains 
are  taken  in  at  the  top  of  the  pipe,  through  drilled  and  tapped  holes. 
Where  more  than  one  length  of  pipe  is  required  the  joint  should 
be  free   from  pockets  or  shoulders.     About   the  only   practical 
method  of  accomplishing  this  is  as  shown  in  Fig.  335    (Ri-2). 
A  lead  ring  is  squeezed  into  the  joint  between  the  flange  and  pipe 
at   the   threads.     The   bore   of   the   flange  is 
machined   the  same  for  both   flanges  and  if 
this  varies  slightly  the  lead  ring  is  trimmed 
with  a  slight  bevel  from  the  end  of  pipe  to  the 
flange.    When  this  flange  joint  is  made  up  the 
bore  is  smooth,  leaving  no  projections  to  cause 
FIG-  335  (Ri-a).       precipitation.     Connections  can  be  made   by 
means  of  a  T  placed  between  the  flanges  shown 
in  Fig.  335,  but  this  will  be  more  expensive  than  to  use  a  larger 
main,  drilled  and  tapped  on  its  upper  side  to  receive  the  branch. 
The  pipe  main  shuts  out  the  dust  from  the  basement  and  also 
permits  steam  being  blown  through  to  clean  it  out,  as  shown  in 
Fig.  114. 

An  open  main,  similar  to  a  roof  gutter,  can  be  made  of  galvanized 
sheet  iron,  or  a  wooden  trough  covered  with  tin  can  be  used.  A 
flat  open  trough  would  retain  many  of  the  impurities  and  relieve 
the  filter  to  this  extent.  Considering  the  use  of  a  device  carrying 
oil,  and  open  to  the  atmosphere,  it  must  be  expected  that  oil  will 
creep  over  the  entire  outside  surface.  Drip  lines  should  be  run 


OIL  PIPING. 


431 


in  warm  places.     The  warmer  the  line  is  kept  the  less  liable  is 
precipitate  to  lodge. 

Class  R2  —  Oil  and  Drip  Lines  to  Cups  and  Machines.     The 

following   few   essentials    in    these   drip    connections    should   be 
provided  for. 

1.  The  connections  to  main  journals,  eccentrics  and  crank-pins 
should  be  arranged  so  that  the  journal  caps  or  oil  guards  can 
be  removed  while  running  and  without  shutting  off  the  oil  supply. 

2.  Different  lines  and  branches  should  have  a  gradual  uphill 
construction,  there  being  a  low  point  which  all  the  branches  will 
drain. 

3.  Pipes  should  be  supported  a  sufficient  distance  from  the 
machine  to  permit  cleaning. 

4.  The  oiling  system  for  each  machine  should  be  a  unit  in 
itself  operative  without  the  general   oiling  system   and  capable 
of  being  changed  over  while  the  machine  is  running. 

The  first  requirement  is  shown  in  Fig.  336  (R2-i),  the  pipes 
swinging  on  their  threaded  joints.  If  valves  were  used  in  each 
of  the  swing  connections  they  would  be  placed  at  A,  this  being 
necessary  in  order  to  disconnect  the  cups 
from  the  journals.  Valve  B  is  the  throttle 
and  the  tee  shown  at  C  is  pointed  down,  with 
a  valve  or  plug  at  its  lower  end.  For  the 
third  requirement  some  post  form  of  support 
of  the  type  used  for  plumbing  fixtures,  as 
shown  in  Fig.  337  (R2-2),  is  very  desirable. 
Fig.  338  (R2~3)  is  objectionable  unless  the 
post  has  a  right-and-left  thread.  The  screw 
holes  for  the  support  shown  in  Fig.  337  can 
be  drilled  with  a  breast  drill,  but  for  Fig.  338 
a  ratchet  drill  must  be  used.  The  distance 
from  the  pipe  to  the  engine  frame  need  not 
be  great  —  i  J  in.  on  small  pipe  and  2  in.  on 
larger  ones,  this  distance  being  quite  convenient 
to  allow  passing  a  piece  of  waste  through. 

The  fourth  requirement  is  quite  essential  as  its  non-observance 
affects  continuous  operation.  It  requires  an  emergency  tank, 
located  between  the  oil  throttle  and  the  journals,  permitting 
engine  oil  to  be  supplied  in  large  quantities.  Emergency  tanks  can 


FIG.  336  (R2-i). 


432 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


be  kept  away  from  the  engine,  the  valves  placed  at  a  high  point 
and  the  tanks  attached  when  required,  using  the  oil  in  the  combined 
cup  until  the  emergency  tank  can  be  attached  and  filled,  thereby 
making  a  very  reliable  arrangement. 

The  different  drains  may  be  attached  to  a  drip  pot  located 
in  the  main.  This  avoids  the  necessity  of  running  many  branches. 
The  joining  of  drips  with  a  tee  is  a  very  crude  detail.  It  should 

be  an  invariable  rule  that  no  drip 
branch  shall  be  run  that  cannot  be 
cleaned  from  end  to  end  by  passing 
a  wire  through  it.  The  drip  pot, 
Fig.  339  (R2-4),  is  especially  suited 
for  basements  where  the  drips  are 

FIG.  338  (R2-3).    located    close    to    the    ceiling;     T.hat 
shown  in  Fig.  340  (R2~5)  is  suited 

for  drip  lines  built  in  the  cement  floor.  These  drip  pots  are 
of  size  to  take  six  or  eight  drains,  one  pot  to  take  three  or  four 
drains  at  one  point  and  discharge  into  the  next  pot,  the  next  pot 
to  take  four  or  five  more  and  discharge  into  another,  one  engine 


FIG.  339  (R2-4). 


FIG.  340  (R2-s). 


having  possibly  three  pots,  including  the  one  located  in  the  main. 
When  pots  are  used  there  is  no  occasion  for  using  valves  in  the 
branches  or  other  means  for  cleaning  except  by  wire  from  pot 
to  pot. 

The  ordinary  method  of  draining  the  engine  bed  and  pans 
is  to  drill  and  tap  a  small  opening  with  which  the  drip  pipes  are 
connected  from  below.  Some  engine  beds  have  drains  carried 
to  one  side,  possibly  half  in  and  half  out  of  the  floor,  the  details 
employed  being  insufficient  to  provide  for  the  proper  flow  of  the 
oil  and  likely  to  become  damaged.  The  drip  pot  shown  in 


OIL  PIPING. 


433 


Fig.  341  (R2-6)  should  be  provided,  there  being  hardly  any 
other  detail  that  can  be  employed  to  keep  vibration  strains  from 
the  pipe  and  also  make  renewals  possible. 

Modern  practice  requires  but  little  piping  for  cylinder  lubricators 
other  than  that  furnished  with  the  engine.  Force  feed  lubricators 
are  used  almost  exclusively.  They  are  economic  and  positive 
in  operation.  There  is  chance  for  considerable  loss  due  to  care- 
less use  of  cylinder  oil  when  it  is  supplied  from  a  pipe  line.  When 
the  drop,  sight  feed  lubricator  was  extensively  used,  there  were 


FIG.  341  (R2-6). 

various  methods  of  piping  the  lubricators,  as  shown  in  Figs.  54  to  57. 
For  large  power  plants  the  cylinder  oil  supply  system,  shown  in 
Fig.  58,  may  be  found  convenient  and  clean.  The  saving  in  oil 
and  labor  will  be  slight,  but  as  the  piping  for  such  a  system  is 
inexpensive,  it  may,  in  an  indirect  way,  be  a  profitable  investment, 
as  it  aids  in  securing  cleanliness  in  the  plant. 

The  method  of  feeding  cylinder  oil  to  the  steam  valves  and 
the  cylinder  has  much  to  do  with  the  economical  use  of  the  oil, 
it  often  being  possible  to  reduce  the  consumption  fully  one-half. 
Oil  should  be  fed  to  the  valves  as  close  to  the  cylinder  as  possible. 
The  quantity  of  animal  fat  required  in  an  oil  is  determined  by  the 


434 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


FIG.  342  (R2-7). 


amount  of  condensation  in  the  cylinders.     The  animal  fats  should 

have   the   least   possible    exposure   to   high   temperature    steam. 

Animal  fats    are  the  only  lubricants  that  will  adhere  to  the  wet 

walls  of  cylinders,  therefore  the  drier  the  cylinder  walls  the  less 
animal  fat  will  be  required,  thus  permitting 
the  use  of  a  much  heavier  mineral  oil.  This 
will  require  atomizing  at  a  considerable  distance 
from  the  cylinder.  Such  heavy  oil  is  a 
permanent  lubricant  and  will  stand  coming 
in  contact  with  high  temperature  steam. 

Atomizers  for  use  in  steam  pipes  serve  the 
same  purpose  as  feeding  in  the  oil  higher  up 
in  the  pipe.  The  oil  is  broken  up  when  it 
leaves  the  atomizer  and  does  not  depend  upon 
the  heat  of  the  steam  to  be  thoroughly 

vaporized.     A  vaporizer  is  particularly  valuable  in  the  use  of  oil 

containing  animal  fats,  as  it  shortens  the  distance  and  time  that 

these  fats  are  exposed  to  steam  be- 
fore precipitation  on  cylinder  walls. 
One  form  of  atomizer  is  shown 

in    Fig.    342    (R2~7).     The    chief 

requirement  of  this  device  is  that 

no  part  can  become  loosened  and 

carried  into  the  engine.     The  long 

foot  or  stem  projecting  downward 

from  the  atomizer  prevents  the  head 

from  unscrewing.     Another  method 

of  use  is  to  have  the  atomizer  head 

smaller   than   the   opening   in    the 

pipe,  made  in  one  piece  and  screwed 

in     from     the    outside.       A    most 

satisfactory  lubricator  is  shown  in 

Fig-     343    (R2-8).       As    the    oil 

receptacle  incloses  the  entire  pump 

mechanism  the  receptacle  is  free  from  all  working  parts,  being 

held  in  place  by  two  winged  nuts  on  the  end  of  two  eyebolts. 

The  receptacle  can  be  removed  while  the  pump  is  in  operation 

and  oil  fed  to  the  pump  suction  direct.     A  stroke  adjuster,  which 

moves  with  the  plunger,   shows  the  movement  of  each  of  the 

plungers. 


r  F---, 

q///fKterf/0fte*  -  - 


Iffe/nerab/e  (?//  Case  I 
FIG.  343  (R2-8). 


OIL   PIPING.  435 

Some  Corliss  engines  have  lubricators  with  five  feeds,  but  this 
is  not  the  best  practice  for  the  economical  use  of  oil.  There 
would  be  in  this  case  one  feed  at  each  end  of  the  two  admission 
valves,  and  the  other  feed  into  the  packing  rings.  The  latter  feed 
is  desirable  if  fed  between  the  inner  and  outer  ends  of  packing, 
requiring  in  this  case  as  much  pressure  to  deliver  oil  to  packing 
as  will  be  required  to  deliver  it  into  steam  space.  The  lubrica- 
tor ordinarily  should  have  three  feeds  —  one  to  the  rod  as  noted 
and  one  a  short  distance  above  the  throttle  valve  with  an  atom- 
izer, as  shown  in  Fig.  342.  There  should  be  another  feed  higher 
up  in  the  steam  pipe  for  emergency  use. 

With  four  lubricator  feeds  in  use,  it  is  difficult  to  get  men 
accustomed  to  proper  feeding.  The  general  tendency  is  to  use 
too  much  oil,  which  is  detrimental  to  proper  lubrication  —  it  is 
more  difficult  to  break  up  a  large  drop  of  oil  than  a  small  one. 

The  oil  cup  shown  in  Fig.  344  (R2-g)  has  many  commendable 
features.  Oil  from  the  pipe  line  can  be  discharged  to  a  journal  or 
cup  and  oil  from  the  cup  can  be  discharged  to  the  journal.  The 
cup  can  be  filled  by  rotating  the  cock  shown.  The  handle  of  the 
cock  is  balanced  and  shows  the  position  of  the  parts.  The  ends 
of  the  cock  are  packed,  affording  sufficient  friction  to  hold  it  in 
any  position  in  which  it  may  be  placed,  without  leakage.  The 
needle  valve  utilizes  its  packing,  more  to  retain  set  than  to  prevent 
leaks,  as  there  is  no  pressure  past  the  valve.  In  regular  operation 
the  line  is  shut  off  with  the  cock  and  the  needle  valve  left  undis- 
turbed ready  to  feed  the  desired  amount  when  the  engine  is  again 
started.  If  the  oiling  system  is  under  pressure  before  the  engine 
starts,  the  oil  cups  at  the  top  of  the  oil  regulator  are  left  cff. 
Instead  of  using  glass  body  storage  cups,  they  may  be  made  of 
light  sheet  metal,  as  shown  in  Fig.  345  (R2-io),  and  shaped  to 
stack  up  in  close  quarters  and  be  ready  for  use  if  required. 

Another  type  of  oil  feeder  is  the  automatic  oil  cup  or  valve 
arranged  to  close  when  the  oil  throttle  is  closed  and  open  with  the 
throttle.  This  type  of  valve  is  shown  in  Fig.  346  (R2-n)  and 
to  make  the  system  reliable  an  emergency  tank  must  be  used,  as 
shown  in  Fig.  59.  This  automatic  valve  consists,  primarily,  of 
a  free  moving  piston  with  a  valve  at  its  lower  end.  The  pressure 
moves  the  piston  from  the  valve  seat  as  far  as  the  set  of  the  regu- 
lating screw  will  permit  and  a  spring  closes  the  valve  when  the  oil 
pressure  is  off.  Any  leakage  that  may  pass  the  piston  will  flow  over 


436 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


its  edge  and  be  discharged  through  a  port  in  the  center  of  the 
regulating  valve.  When  the  piston  closes  the  regulating  valve 
it  also  closes  the  valve  in  the  open  end  of  the  piston,  shutting  off 
any  oil  that  otherwise  would  leak  past  the  piston.  The  union 


FIG.  344 


FIG.  346  (R2-n). 


connection  to  the  sight  post  is  the  same  as  shown  in  Fig.  344. 
This  permits  a  pipe  connection  and  a  position  of  sights  to  suit  the 
requirements.  The  valve  in  this  cup  remains  at  the  end  of  the 
pipe  when  the  cup  is  disconnected  from  the  journal,  the  same 
as  in  Fig.  344.  When  it  is  necessary  to  change  over  to  the  low- 
pressure  gravity  system  the  adjusting  screw  is  run  out  and  the 
valve  mechanically  lifted  from  its  seat.  The  spring  used  for  low- 
pressure  cups  is  light,  so  that  the  pressure  will  force  back  the  piston 
and  open  the  valve.  The  high  pressure  requires  a  spring  that  will 
close  more  firmly  but  not  so  accurately  as  with  fitted  valve  faces. 
The  parts  of  this  cup  are  few  in  number  and  as  each  is  heavy 
there  is  practically  no  danger  of  the  parts  becoming  damaged. 

Class  R3  — Oil  and   Drip  Lines  for  Oil  Pumps.     Any  of  the 
pumps  ordinarily  used  for  water  can  be  used  to  pump  oil  if  the 


OIL  PIPING. 


437 


oil  can  be  kepi  free  from  water.  The  animal  fats  have  an  affinity 
for  both  oil  and  water  and  if  the  oil  contains  or  takes  up  animal 
fats  it  is  then  in  condition  to  absorb  water.  Oil  in  this  condition 
cannot  be  agitated  without  foaming  and  where  the  oil  is  used 
many  times  these  fats  are  sure  to  be  taken  on  and  considerable 
water  be  absorbed  by  the  oil. 

The  duty  of  an  oil  pump  is  generally  so  light  that  the  greatest 
difficulty  is  encountered  in  handling  small  quantities  of  oil;  for 
instance,  if  a  3  by  2  by  3  in.  steam  pump  be  used,  pumping  half 
a  barrel  of  oil  each  hour,  then  the 
pump   would   make  but  10  strokes 
per  minute  or  a  total  piston  travel 
of  but  2.5  ft.  per  min.     If  the  steam 
line    to   the   pump  were   only  ordi- 
narily exposed  to  radiation,  the  con- 
densation   would    almost    stop    the 
pump.     For    handling    so   small    a 
quantity  of  oil  at  a  pressure  of  15  Ib. 
per  sq.  in.  a  drive  equal  to  0.004  hp. 
will  be  required  to  operate  the  pump. 

The  pump  arrangement  shown 
in  Fig.  347  (R3~i)  is  specially  suited 
for  oil  systems.  The  speed  of  crank 
A  can  be  kept  constant,  power  being 
taken  from  a  small  motor  as  shown. 
The  wear  and  tear  on  the  motor  is 
much  less  by  allowing  it  to  run  con- 
tinuously. The  pin  and  slide  box, 
By  require  a  vertical  travel,  whether 
it  completes  a  circle  in  its  travel,  or 
but  a  segment,  as  would  be  the 

case  if  attached  to  a  rocker  arm.  Pressure  on  the  oil  is  exerted  by 
the  weight,  C,  the  driving  mechanism  simply  raising  the  weight 
of  each  stroke.  If  no  oil  is  used,  the  weight  will  remain  elevated. 
The  pump  should  be  located  in  the  oil  tank  for  the  reason  that 
any  leakage  past  the  piston  will  then  flow  directly  back  to  the 
tank.  The  plunger  should  have  a  long  bearing  in  the  cylinder, 
not  less  than  four  inches  in  any  part  of  the  stroke.  The  connec- 
tion to  the  rod  at  the  top  of  the  plunger,  D,  should  be  of  the  ball 
form,  so  that  it  may  be  free  to  turn.  The  anchor  block,  £, 


FIG.  347  (R3-i). 


438 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


receives  the  T  end,  which  is  a  part  of  the  pump  cylinder.  The 
air  chamber,  G,  is  not  absolutely  necessary,  but  serves  to  minimize 
variations  in  the  pressure.  The  slot  in  the  connecting  rod,  H' 
must  be  of  sufficient  length  to  permit  a  complete  revolution  of  the 
crank  without  moving  the  connecting  rod.  The  spring  cushions 
the  shock  of  the  slide  box,  B,  striking  the  open  end  of  the  con- 
necting rod  and  compressing  as  weight  C  obtains  speed.  The 
guide,  K,  takes  the  side  thrust  of  the  pump  rod.  If  a  small  motor 
is  used,  it  will  be  advisable  to  use  a  counterweight  opposite  the 
pin,  By  as  shown  at  L.  This  counterweight  should  have  about 
half  the  weight  of  that  lifted  by  the  pin,  B.  The  pump  can  make 
as  high  as  100  strokes  per  minute  with  a  0.75  in.  plunger  and 
3-in.  stroke  and  work  satisfactorily. 


Connect  fo  J&/TJG 
Parf 


FIG.  348  (R3-2). 


%w///////////w^^ 

FIG.  349  (R3-3). 


Instead  of  the  oil  pump  being  located  inside  of  the  tank,  it 
may  be  located  elsewhere  with  pipe  connections  as  shown  in 
Figs.  348  (R3-2)  and  349  ^3-3).  The  oil  supply  pipe,  A, 
standpipe,  B,  and  port  to  suction  valve,  C,  are  at  all  times 
open  to  each  other,  a  port  running  from  chamber  B  to  port  C, 
with  pipe  A  connecting  them.  A  discharge  port,  D,  is  carried 
down  to  one  side  past  the  discharge  valve  and  connects  with 
discharge  pipe,  E.  It  will  be  noted  that  this  pump  is  quite  free 
from  friction  and  there  is  no  chance  of  oil  slopping  around  it. 
The  valve  and  plunger  stand  vertically.  Fig.  349  shows  the 
pump  operated  from  a  bell  crank.  The  pump  shown  in  Fig.  348 


OIL  PIPING.  439 

is  well  adapted  to  deliver  oil  to  an  overhead  tank,  the  bell-crank 
working  full  stroke  all  the  time,  and  if  desired  the  escapement 
shown  in  Fig.  347  may  be  omitted.  However,  this  detail  is  so 
simple  and  has  so  little  wear  that  its  use  would  be  advisable  if 
for  no  other  purpose  than  to  be  able  to  maintain  oil  pressure 
without  the  gravity  tank  when  this  tank  is  being  cleaned  or 
repaired.  If  the  engine  has  an  emergency  oil  supply,  as  shown  in 
Figs.  344  and  345,  it  will  be  safe  to  operate  without  the  gravity 
tank,  using  simply  the  filter,  pump  and  oil  storage,  shown  in 
Fig.  349,  to  which  all  the  drains  are  run,  and  deliver  oil  by  hand 
to  the  oil  cups  during  such  time  that  any  portion  of  the  system 
is  out  of  service. 

Placing  all  the  engines  on  one  oiling  system  is  not  the  best  prac- 
tice, as  a  slight  trouble  will  affect  the  entire  station.  An  advan- 
tage in  having  a  separate  system  for  each  engine  is  that  different 
oils  can  be  used  for  different  engines,  according  to  the  needs. 

Class  R4  —  Oil  and  Drip  Lines  for  Filters  and  Purifiers.  There 
are  many  types  of  apparatus  for  removing  undesirable  properties 
from  the  oil.  The  following  are  the  impurities,  so  called,  that 
must  be  removed  to  keep  the  oil  in  the  best  condition : 

1.  Solid  substances  of  measurable  size,  removed  by  filtration. 

2.  Solid  substances  of  very  small  size,  removed  by  precipitation. 

3.  Fats  and  heavy  oils,  removed  by  allowing  oil  to  stand  perfectly 
still  and  precipitate. 

4.  Free  water,  removed  by  precipitation. 

5.  Water    incorporated    and   held    in   suspension   by   the   oil, 
removed  by  evaporating  the  water  from  the  oil. 

The  ordinary  commercial  filter  accomplishes  the  first  and 
to  a  slight  extent  the  second,  but  little  attempt  is  made  to  meet 
the  third,  fourth  and  fifth  requirements.  To  properly  perform 
the  second  and  third  requirements,  it  is  necessary  to  remove  the  oil 
entirely  from  circulation  for  a  considerable  time,  say  from  four  to 
six  weeks.  The  fourth  requirement  can  quickly  be  accomplished 
with  an  automatic  water  discharge  placed  between  the  drip  main 
and  the  filter,  preventing  the  free  water  from  reaching  the  filter. 
The  fifth  requirement  requires  a  special  device  which  should  be 
used  occasionally,  say  once  a  month,  all  the  oil  passing  through 
it  at  that  time. 

There  are  two  general  types  of  filters,  one  having  a  small 
filtering  area  and  great  depth,  the  other  having  a  large  area  and 


440 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


slight  depth.  Wire  screen  trays  are  easily  cleaned  and  a  large 
part  of  the  filtering  can  be  done  with  them,  the  final  filtration  to  be 
carried  on  through  some  fine  mesh  material  such  as  felt  or  bone 
charcoal.  The  screens  should  be  so  placed  that  they  ma/  be 
removed  one  at  a  time  and  the  deposits  blown  out  with  steam. 

The  fourth  requirement  should  be  cared  for  before  the  oil 
reaches  the  filter,  as  oil  and  water  make  a  wet,  greasy  surface 
which  is  repellent,  making  the  movement  through  the  filter  very 
slow.  Water  can  readily  be  removed  from  the  oil  by  the  use  of 
an  automatic  separator,  as  shown  in  Fig.  350  (R4~i).  The 
operation  of  this  separator  depends  upon  the  difference  in  gravity 
of  oil  and  water.  The  column  of  oil  above  line  A  is  maintained 
at  the  same  weight  as  a  column  of  water  above  the  same  line.  If 
an  increase  in  the  amount  of  oil  lowers  the  line  A-  A  slightly,  then 
the  oil  column  will  weigh  less  than  the  water  column  and  the  top 


oaseCorer 


we  flow 


FIG.  350  (R4-i). 


FIG.  351  (R4-2). 


surface  of  the  water  will  fall  below  the  edge  of  overflow  and  cause 
the  oil  surface  to  be  relatively  higher.  The  oil  and  water  overflows 
should  be  long  so  that  the  discharge  will  not  rise  over  them  suffi- 
ciently to  greatly  disturb  the  line  between  the  oil  and  water.  For 
each  inch  difference  in  the  height  of  the  overflows  a  column  of 
10  in.  of  oil  can  be  carried.  One  and  one-half  inches  difference 
will  permit  15  in.  of  oil  above  the  water.  The  inlet  pipe  crosses 
the  separating  tank  and  has  holes  along  the  bottom  and  sides, 
the  water  tending  to  discharge  through  the  lower  and  oil  out  of 
the  side  holes.  The  inlet  is  shown  in  the  oil  space  as  it  is  pref- 
erable to  bring  the  oil  in  contact  with  as  little  water  as  possible  and 


OIL   PIPING.  441 

thus  avoid  increasing  the  quantity  of  water  incorporated.  This 
separator  will  become  very  dirty  and  to  facilitate  cleaning  there 
should  be  a  wash-out  valve  located  at  the  bottom. 

The  second  and  third  requirements  necessitate  putting  the  used 
oil  out  of  service;  the  method  of  doing  this  is  shown  in  Figs.  61 
and  62.  This  precipitating  tank  should  be  located  in  the  base- 
ment and  used  for  no  other  purpose.  The  contents  of  a  filter 
should  be  discharged  into  an  overhead  gravity  tank,  the  filter 
being  cleaned  and  filled  with  settled  oil.  The  precipitation  tank 
should  have  its  contents  entirely  out  of  circulation  and  be  as 
free  from  vibration  as  possible.  For  successful  precipitation, 
the  following  requirements  should  be  provided  for: 

1.  In  removing  the  clear  settled  oil  from  precipitation  tank  the 
contents  should  not  be  agitated. 

2.  The  clean  oil  should  be  passed  over  only  clean  surfaces. 

3.  The  discharge  should  readily  be  apparent,  showing  clearly 
if  it  is  top  oil,  bottom  oil  or  water. 

4.  Means  should  be  provided  for  saving  the  bottom  oil,  to  be 
used  elsewhere. 

5.  Means  should  be  provided  for  the  thorough  cleaning  of  the 
tank. 

The  above  requirements  are  well  provided  for  in  the  precipitation 
tank  shown  in  Fig.  351  (R4~2).  The  contents  of  the  tank  are 
raised  by  admitting  water  from  the  "  spreader  "  at  the  bottom 
of  the  tank.  This  spreader  is  constructed  similar  to  a  gas  burner, 
with  many  small  openings  so  arranged  that  the  current  of  the  water 
is  broken  up  and  discharged  into  the  bottom  of  the  tank  without 
causing  agitation.  The  thin  layer,  A,  is  the  heavy  oil  which  has 
precipitated  out  of  the  upper  light  oil.  It  is  easy  to  raise  oil  and 
water  and  not  cause  them  to  mix;  but  to  keep  the  oil,  A,  at  the 
bottom  and  not  have  it  mix  with  the  oil,  B,  requires  a  spreader 
well  designed  and  water  fed  slowly  into  the  tank.  The  three 
valves  at  C  control  the  overflow,  one  line  leading  to  the  filter, 
another  to  an  oil  barrel  and  a  third  to  the  sewer,  used  only  in 
washing  out.  The  cone  at  the  top  of  the  tank  is  made  of  glass, 
the  line  between  light  and  heavy  oil,  also  the  line  between  heavy 
oil  and  water,  being  readily  noted  as  it  rises  and  passes  the  cone. 
The  overflow  ring,  D,  and  reflector  bar,  E,  are  nickel  plated  and 
polished.  The  distance  between  the  glass  and  the  reflector  bar 
is  J  in.  and  shows  clearly  the  line  between  dark  and  light  oil.  If 


442  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

the  overflow,  Z>,  were  only  used  as  shown  in  the  enlarged  view, 
the  oil  would  lie  on  the  top  surface  as  at  F  and  water  would  con- 
tinue to  flow  from  under  it. 

After  the  oil  is  raised  from  the  tank  then  the  spreader  is  removed 
by  means  of  an  extension  handle  and  the  inside  of  the  tank  is  ready 
to  be  cleaned.  A  very  satisfactory  style  of  cleaner  is  shown  in 
Figs,  in  and  112.  The  tank  has  a  cone-shaped  shell,  both  to 
facilitate  cleaning  and  also  to  reduce  agitation  of  the  oil  when  it  is 
being  raised  with  the  water.  Instead  of  the  cone  being  entirely 
of  glass  it  may  be  of  metal  with  a  slit  covered  with  a  narrow  strip  of 
glass  and  the  reflectors,  D  and  £,  attached  to  the  cone.  A  loose 
inverted  cone  top  must  in  any  case  weigh  more  than  the  oil  it 
displaces,  to  prevent  it  from  floating.  Fig.  352  (R4~3)  shows 


Stcr/o/v /?.&. 
FIG.  352  (R4-3)- 

a  metal  top  and  section  A-B  shows  glass  set  in  a  frame  of  stiff 
metal.  The  reflector  is  set  J  in.  away  from  the  glass  and  has  a 
sufficient  number  of  holes  in  it  to  permit  oil  to  reach  the  glass  at 
all  points  from  the  bottom  to  the  top.  The  glass  alone  is  not 
sufficient  to  indicate  the  contents.  It  is  necessary  for  light  to  pass 
through  the  oil  to  enable  the  operator  to  determine  the  contents 
of  the  tank.  A  cone  top  permits  drawing  off  practically  all  of 
each  grade  of  oil,  as  there  will  be  but  a  narrow  ring  remaining 
at  the  overflow,  the  entire  center  being  taken  up  by  the  cone. 
Instead  of  oil  J  in.  deep  covering  a  i6-in.  round  section  there  is 
only  a  ring  £  in.  deep  and  J  in.  wide  of  the  same  size  section. 

In  considering  the  use  of  a  precipitating  tank  the  storage  space 
in  the  filter  permits  but  a  partial  precipitation  and  the  most 
conclusive  evidence  that  something  more  than  a  filter  is  required 
can  be  found  in  the  oil  as  used.  When  the  oil  is  new  it  will  run 
through  the  filter  freely,  but  when  it  has  been  used  for  some 
time  it  is  necessary  to  heat  it  in  order  to  force  it  through  the  filter. 
The  longer  the  oil  is  used  the  more  sluggish  it  becomes  and  the 
more  heat  is  required.  If  the  filter  were  removing  all  the  unde- 
sirable properties,  it  would  not  be  necessary  to  heat  the  oil  to 
enable  it  to  pass  the  filter.  The  filter  does  the  rough  work  in 


OIL   PIPING. 


443 


purifying  the  oil,  but  a  precipitation  tank  is  needed  to  complete 
the  process.  By  the  use  of  a  precipitation  tank  immeasurably 
fine  impurities  and  the  heavy  oil  and  animal  fats  are  separated  and 
the  oil  deprived  of  the  means  of  conveying  water  in  suspension. 
Only  by  allowing  the  mixture  to  remain  perfectly  still  for  about 
a  month  can  the  heavier  oils  and  incorporated  water  be  made  to 
precipitate. 

Another  method  for  removing  water  from  oil  utilizes  a  heater 
and  a  blower  for  passing  air  at  a  temperature  of  140  degrees 
through  the  oil.  This  method  is  unsatisfactory  because  it  does 
not  remove  the  fats  which  again  take  up  water. 


FIG.  353  (R4-4). 

In  the  piping  system  in  Fig.  353  (R4~4)  the  filters  are  shown 
half  full,  it  being  possible  at  any  time  to  empty  either  by  dis- 
charging the  drips  into  the  other. 

A  water  separator  is  shown  so  arranged  that  when  being  cleaned 
its  filter  connection,  F,  can  be  raised.  The  water  in  such  filters  can 


444 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


be  discharged  through  the  washouts.  The  trap  in  drip  main,  G, 
prevents  any  drips  from  passing  the  water  separator  when  con- 
nection, F,  is  down.  Trap,  H,  likewise  prevents  drips  from 
backing  into  the  water  separator  when  it  is  being  cleaned.  A 
swivel  connection,  /,  permits  the  use  of  either  or  both  of  the  niters. 
The  precipitating  tank,  C,  is  shown  in  Fig.  351,  with  the  oil  over- 
flow sufficiently  high  so  that  oil  will  discharge  by  gravity  into  the 
filter.  The  pumps,  D,  are  like  those  shown  in  Fig.  348  and 

preferably  motor  driven  as  shown 
in  Fig.  347.  It  is  necessary  that 
two  pumps  be  used  to  enable  repairs 
to  be  made  to  the  pumps  and  to 
permit  filling  the  precipitating  tank 
with  dirty  oil  from  one  of  the  filters 
while  the  other  pump  is  supplying 
the  bearings.  The  crossover  con- 
nection, 7,  enables  both  filters  to 
be  in  use  with  but  one  pump  in 
operation.  The  crossover,  K,  is 
necessary  to  permit  the  contents  of 
either  filter  to  be  discharged  into 
the  precipitating  tank.  The  num- 
erous valves,  L,  in  the  oil  mains 
insure  that  only  one  machine  will  be  shut  down  if  there  is  any 
trouble  with  an  oil  main. 

If  two  or  more  filters  were  used,  connections  as  shown  in  Fig.  353 
would  be  unsatisfactory,  because  the  drips  would  then  flow  to 
the  lowest  connection.  In  the  arrangement  shown  in  Fig.  354 
(R4~5)  the  oil  flows  from  one  filter  into  another,  the  clean  filters 
doing  the  larger  amount  of  work.  This  method  is  objectionable 
because  it  requires  that  the  joint,  A,  be  broken  whenever  the 
storage  tank  is  cleaned. 

The  water  gage  and  the  line  to  the  pump  are  located  at  the 
lowest  possible  point.  The  levels  in  the  different  filters  are 
maintained  alike  with  the  construction  such  as  will  permit  oil  to 
flow  from  one  tank  to  another.  The  center  of  the  filtering  cylinder 
is  open,  and  through  this  central  opening  at  the  bottom  the  filter- 
ing tube  can  be  plugged.  In  this  manner  the  cylinders  can  be 
removed  one  at  a  time  without  interfering  with  the  operation  of 
the  other  cylinders. 


FIG.  354  (R4-5)- 


OIL  PIPING. 


445 


Class  R5 — Oil  and  Drip  Lines  for  Oil  Storage.  In  making  proper 
provision  for  oil  storage  it  is  necessary  to  consider  the  following 
questions: 

1 .  Has  the  power  plant  owner  a  sufficiently  large  oil  storage  house  ? 

2.  Can  a  saving  be  effected  by  receiving  oil  in  carload  lots? 

3.  Must  other  than  the  power  station  draw  on  the  stock? 


CIXYXQ 

MMa FT-v-r-cr- 


cnooQO 


nnnnnni 


-Poors/// 


OOOOOOI 


FIG-  355 


FIG.  356  (Rs-2). 

Fig.  355  (RS-i)  shows  an  oilroom  with  a  hydraulic  lift  for 
raising  or  lowering  barrels.  A  room  14  ft.  square  is  of  sufficient 
size  to  store  a  carload  of  oil  in  barrels.  An  emptying  sink  is 
located  next  to  the  window  and  close  to  the  hoist.  From  this 


446  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

sink  a  number  of  lines  run  to  the  filters  and  stock  tanks.  These 
stock  tanks  are  similar  to  those  shown  in  Fig.  58,  with  the  tanks 
outside  of  the  barrel  room,  as  it  is  desirable  to  keep  the  tanks 
warm  and  also  easier  to  arrange  a  scale  to  show  the  amount  of  oil 
used  by  each  shift. 

Another  arrangement  for  oil  storage  is  that  shown  in  Fig.  356 
(R5-2),  which  shows  three  storage  tanks  with  a  receiving  sink 
located  outside  of  the  building,  this  sink  being  provided  with 
waste  or  other  filtering  material  to  prevent  impurities  reaching 
the  storage  tank.  If  air  pressure  is  available,  then  the  cylinder  oil 
tanks  may  have  dished  heads,  both  top  and  bottom,  and  the  air 
pressure  be  used  to  deliver  oil  to  the  engine  room  floor. 

Class  R6  —  Oil  and  Drip  Lines  for  Hand  Devices.  On 
account  of  the  numerous  places  around  the  engine  room  where 
engine  oil  is  required  it  is  necessary  to  provide  several  oil  taps. 
If  the  plant  consists  of  large  units,  it  would  be  well  to  locate  an  oil 
tap  at  each  machine.  Such  taps  could  be  attached  to  the  regular 
piping  system  of  the  unit,  in  some  easily  accessible  spot,  preferably 
over  some  drip  pan  of  the  machine. 

The  quantity  of  oil  used  daily  is  easily  accounted  for  with 
the  system  as  shown  in  Fig.  355;  the  records  show  just  how  much 
cylinder  oil  has  been  used,  also  how  often  a  barrel  of  engine  oil  is 
added  to  the  oiling  system.  With  the  system  shown  in  Fig.  356 
it  is  not  so  easy  to  keep  the  record  from  day  to  day,  as  the  size  of 
the  oil  tanks  makes  accurate  readings  impossible.  By  the  use  of 
one  or  two  small  tanks,  as  shown  in  Fig.  355,  it  is  possible  to  keep  a 
very  accurate  record  of  the  oil  consumption  by  having  these  tanks 
filled  to  a  certain  level  each  day  and  having  each  shift  report  the 
oil  level  at  beginning  and  end  of  the  watch.  Whatever  method  is 
employed  to  supply  the  measuring  tanks  should  be  safeguarded 
against  the  possibilities  of  any  manipulation. 

The  small  measuring  tank  shown  in  Fig.  357  (R6-i)  has  a 
float  tell-tale  instead  of  gage  glass.  The  tell-tale  is  somewhat  less 
liable  to  injury  and  derangement,  as  there  is  neither  a  packing  nor 
glass  tube  to  keep  in  order.  The  tank  should  be  of  small  diameter, 
say  &  in.,  and  5  ft.  long  if  not  over  8  gal.  of  oil  is  used  each  day.  In 
considering  the  use  of  air  and  water  to  raise  oil,  it  must  be  noted 
that  the  storage  tank  may  require  a  large  volume  of  air  to  raise 
possibly  one  cubic  foot  of  oil  into  the  measuring  tank.  Water 
would  be  quicker  to  act,  but  if  water  were  used  special  care  would 


OIL  PIPING. 


447 


have  to  be  taken  to  avoid  the  possibility  of  destructive  pressure 
being  put  on  the  storage  tank.     The  use  of  water  introduces  a 

feature  which  might  cause 
serious  oil  loss  due  to  the  fact 
that  water  used  to  raise  the  oil 
must  be  run  to  the  sewer  when- 
ever the  storage  tank  is  to  be 
filled.  Unless  closely  watched  the 
water  might  all  run  out  and  con- 
siderable oil  waste  to  the  sewer. 
The  use  of  air  eliminates  the  pos- 
sibility of  oil  losses  from  this  cause. 


G/arft/afetf  Jca/e-  » 


Ze/v 


Jt/pp/y 


Scrrt&s 


The  system  shown  in  Fig. 

357  would  serve  for  both  the 

high  and  low  pressure  cylinder 

oils.     There  would  be  little  or 

no  object  in  having  a  separate 

tank  for  new  engine  oil.  The  FlG  357  (R6-i). 

operators  would  not  use  it  if 

their  shift  were  to  be  charged  with  it — they  could  get  oil  from  the 

return  drip  system.  The  use  of  oil  in  the  boiler  room  for  feed 

pumps,  stoker  engines,  etc., 
can  be  best  accounted  for  by 
making  the  engineer  in  charge 
of  the  shift  accountable.  The 
usual  method  of  recording  at 
the  end  of  a  shift  is  for  the 
engineer  quitting  and  the  one 
coming  on  to  go  to  all  the 
lubricators  and  other  devices 
that  hold  a  quantity  of  oil  and 

see   that   the   oil   is    brought   up    to   the    established    "  quitting 

line."     When  tanks  are  restocked    the  engineer  in  charge   and 


FIG.  358  (R6-2). 


448  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

the  stockkeeper  take  readings   together  and   the   tank   is  then 
filled. 

To  facilitate  the  emptying  of  the  barrels  and  to  avoid  putting 
vent  holes  in  them  there  should  be  a  barrel  valve  used,  as  shown 
in  Fig.  358  (R6-2).  This  barrel  valve  is  screwed  into  the  bung  hole 
by  a  spanner  wrench.  The  vent  pipe  is  made  curved  and  of  small 
pipe  so  that  if  it  strikes  the  side  of  the  barrel  it  will  not  prevent  the 
valve  from  being  screwed  in.  The  valve  is  of  the  register  type, 
with  two  or  three  oil  openings  and  one  air  opening.  Pin  stops  are 
quite  necessary  to  insure  that  the  valve  will  be  fully  opened  or 
closed.  By  turning  the  spring  upside  down  it  is  possible  to  grind 
the  valve  to  its  face. 


CHAPTER   XXVIII. 
BLOW-OFF  PIPING. 

Class  SI  —  Blow-Off  Main.  The  service  performed  by  a  blow- 
off  main  is  exacting.  The  pressure  and  temperature  variations 
are  such  as  to  cause  much  movement  of  the  lines.  It  is  neither 
customary  nor  necessary  to  install  two  blow-off  mains.  In  Fig.  45 
is  shown  a  duplicate  blow-off  main  which  is  arranged  more  to 
suit  the  requirements  of  condenser  discharge  than  for  any  other 
service. 

Fig.  359  (Si-i)  is  a  sectional  view  of  the  blow-off  basin  shown 
in  Fig.  45.  The  blow-off  pipes  and  the  pipe  hangers  are  of  cast 


FIG.  359  (Si-i). 

iron,  made  necessary  on  account  of  the  moisture  in  the  waterway. 
The  gratings  at  the  top  of  the  basin  are  made  very  open  to  allow 
steam  to  escape  freely.  The  volume  of  water  that  this  basin  should 
hold  is  dependent  upon  the  amount  passing  through  from  the 
condensers.  A  basin  5  feet  square  will  be  found  of  sufficient  size 
in  almost  any  case.  If  the  blow-off  main  is  open  to  the  free  circu- 
lation of  air  and  is  hot  constantly,  it  should  be  of  standard  wrought- 
iron  pipe. 

449 


450 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


Braces  toMW/dr/n  ana 'toeafc Sfofe 


The  main,  back  of  the  boilers,  should  be  in  an  open  trench. 
The  portion  of  the  trench  between  the  boilers  should  have  a  cover 
plate  to  make  the  floor  continuous.  The  form  of  cast  plate 
shown  in  Fig.  360  (81-2)  is  suitable  for  such  work,  as  it  does  not 

require  a  frame.  The  round  cor- 
ner support  does  not  let  the  plate 
damage  the  cement  work.  The 
plate  is  secured  on  the  forms 
and  the  cement  finished  against 
it.  The  pipe  line  should  be  com- 
pleted before  the  cement  work 
is  finished,  thus  saving  time  and 
insuring  a  better  location  of  the 
pipe  and  less  damage  to  the  concrete.  A  brick  trench  can,  in 
many  cases,  be  constructed  more  quickly,  but  concrete  is  better  for 
this  work,  as  it  is  more  permanent. 

The  cover  for  the  trench  is  in  some  cases  of  plank  or  it  may 
be  of  flagging.  In  laying  out  the  trench  care  should  be  taken 
that  sufficient  room  is  provided  so  that  the  lower  bolts  of  the 


'  &/nen/etf  after /~0r/n  0  /ff moved 
FIG.  360  (81-2). 


FIG.  361  (81-3). 


FIG.  362  (Si-4). 


main  shown  in  Fig.  360  may  be  reached.  Fig.  361  (81-3)  shows 
a  wide,  open  trench  back  of  the  boiler  which  gives  ample  room 
around  the  fittings.  Fig.  362  (81-4)  shows  a  similar  space  back 
of  the  boiler  made  into  a  pit  with  a  plank  covering.  These  planks 
should  be  of  oak  and  surfaced,  possibly  4  in.  wide  with  a  i-in. 
space  between  and  all  the  pla.nks  fastened  to  angle  irons  placed 
at  the  ends.  The  pits  back  of  the  boilers  should  have  a  sewer 
drain,  and  the  wide  trench,  Fig.  362,  may  be  pitched  to  the  center 
and  one  catch  basin  serve  many  boilers.  If  the  main  is  of  con- 
siderable length  and  there  are  short,  stiff  branches  connected  to  it, 
it  may  be  necessary  to  use  a  U-bend  to  provide  the  necessary 
elasticity.  The  importance  of  elasticity  should  constantly  be 


BLOW-OFF  PIPING. 


451 


kept  in  mind  in  laying  out  blow-off  connections.  If  cast  iron 
is  used  for  the  main  it  may  be  necessary  to  allow  for  the  movement 
in  the  boiler  branches.  Rather  than  strain  boiler  connections  it 
would  be  better  to  use  a  slip-joint  in  the  main  and  anchor  the  two 
parts  of  main  at  about  their  center. 

Class  82  —  Blow-Off  Branches  from  Boilers.  It  may  be  neces- 
sary to  place  the  blow-off  main  close  to  the  wall  to  secure  elasticity. 
As  shown  in  Fig.  363  (82-1)  the  pipe,  A,  provides  practically  all 
the  elasticity  between  the  boiler  and  the  main  and  should  be  made 
of  standard  weight  pipe.  The  space  shown  back  of  the  boiler  is 


FIG.  363  (82-1). 

wider  than  that  usually  found,  and  if  the  passage  is  narrow,  similar 
to  that  shown  in  Fig.  362,  then  all  the  connections  would  be  very 
stiff.  The  connections  shown  in  Fig.  364  (82-2)  require  a  rather 
elaborate  bend,  but  by  making  it  in  the  form  shown  the  necessary 
elasticity  is  obtained.  It  will  be  noted  that  the  valves  in  Fig.  363 
close  against  the  pressure  and  the  valves  shown  in  Fig.  364  close 
with  the  pressure.  These  are  the  two  principal  types  of  blow-off 
valves. 

One  of  the  best  forms  of  blow-off  connections  is  shown  in 
Fig.  365   (82-3).     The  blow-off  main  is  shown  as  being  in  the 


452 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


engine  room  basement,  an  excellent  arrangement  when  it  can  be 
so  placed,  as  it  requires  no  trench  work,  is  always  open  to  inspection 
and  may  easily  be  repaired.  The  branches  to  the  boiler  are  long 
and  provide  the  necessary  elasticity.  The  only  trench  that  is 


Stcr/o/v 


FIG.  364    (82-2). 


required  is  for  the  connection  to  the  boiler.  The  trench  can  be 
quite  narrow  —  just  wide  enough  to  allow  for  the  movement  of 
the  pipe.  Y-fittings  should  be  used  in  the  main,  as  they  offer  the 
least  resistance  and  cause  the  least  water  hammer.  The  valve 
next  to  the  boiler  should  be  left  open  while  the  boiler  is  in  operation, 

using  the  second  valve  as  the 
regular  operating  valve.  Any 
scale  that  may  pass  the  valve 
plug  will  drop  away  from  the 
seat  and  fall  out. 

Duplicate  valves  are  neces- 
sary in  the  blow-off  connec- 
tion. The  second  one  permits 
of  the  operating  valve  being 
shut  off  from  the  boiler  when- 
ever a  leak  occurs,  affording 
an  opportunity  for  repairs 
while  the  boiler  is  under  pres- 
sure. A  second  reason  is  to 
insure  the  safety  of  a  man 
at  work  inside  of  the  boiler.  When  washing  the  boiler  the  second 
valve  should  be  shut  and  the  bonnet  or  center  piece  of  the  first 
valve^next  to  boiler  removed  to  allow  water  to  discharge  into 
the  pit  under  the  valves. 


FIG.  365  (82-3). 


BLOW-OFF  PIPING. 


453 


The  wash-out  sink  as  shown  in  Fig.  365  should  be  deep  enough 
to  hold  the  scale  that  will  accumulate.  The  pit  shown  in  Fig.  361 
is  well  adapted  to  keep  scale  out  of  the  sewer,  and  with  two  or  more 
catch  basins  a  considerable  distance  apart  it  is  possible  to  shut  off 
the  catch  basin  close  to  the  boiler  and  allow  the  scale  to  accumulate 
in  the  pit.  The  pit  can  be  made  as  shown  in  Fig.  364,  four  feet 
wide  and  full  depth  to  the  wall,  covered  as  shown  in  same  figure. 
The  pit  should  be  about  18  in.  deep  and  the  trenches  10  in.,  allowing 
8  in.  for  the  accumulation  of  scale  at  the  end  of  the  pit. 

Instead  of  the  first  valve  many  boilers  are  fitted  with  a  "washout 
tee  "  and  but  one  blow-off  valve,  with  the  blind  flange  or  cap 
removable.  This  provides  one  advantage  sought  in  the  use  of 
two  valves,  but  fails  to  provide  means  of  insuring  a, tight  valve 
at  all  times.  A  smalLleak  of  but  one-half  pint  a  minute  would, 
in  a  year's  time,  pay  for  an  extra  valve. 


FIG.  366  (82-4). 

If  the  boiler  sets  low  and  the  blow-off  runs  out  below  the  floor 
line,  the  blow-off  connections  may  satisfactorily  be  arranged  as 
shown  in  Fig.  366  (82-4).  The  blow-off  connection  shown  would 
be  quite  impracticable  if  the  wash  water  had  to  be  discharged  into 
the  blow-off  line,  because  the  drum  would  not  drain  freely  and 
the  lower  connection  would  soon  fill  with  scale.  This  trouble, 
however,  would  not  present  itself  when  blowing  out  under  pres- 
sure. If  the  bonnet  of  the  valve  next  to  the  boiler  were  re- 
moved there  would  be  no  pocket  to  fill  with  scale,  nor  would 
it  be  difficult  to  drain  the  drum. 

Class  S3  —  Blow-Off  Branches  from  Economizers.  As  with 
boiler  blow-off  connections,  there  should  be  two  valves  used  for 


454  STEAM    POWER   PLANT  PIPING  SYSTEMS. 

the  economizer  blow-off.  The  valve  next  to  the  economizer 
should  be  so  located  that  its  bonnet  might  be  removed  to  allow 
washings  to  accumulate  and  water  to  pass  to  the  sewer.  If  the 
boiler  room  floor  has  ample  drainage,  then  the  valve  may  be  so 
located  that  any  washings  will  fall  on  the  floor,  allowing  the  water 
to  run  to  the  sewer.  The  first  blow-off  valve  should  not  be  located 
at  a  high  level,  as  the  water  discharged  through  the  bonnet  opening 
would  spatter  most  objectionably. 

Located  at  the  economizer  blow-off  valve  there  should  be 
a  pressure  gage  to  show  how  much  the  pressure  is  being  reduced 
in  the  economizer.  The  valve  can  be  so  manipulated  that  the  pres- 
sure will  not  be  sufficiently  low  to  let  steam  be  generated.  In 
order  to  discharge  water  from  an  economizer  it  is  necessary  for  the 
pump  to  speed  up  and  supply  water  as  fast  as  it  is  blown  out, 
or  steam  will  be  formed  as  a  result  of  the  drop  in  pressure  and 
the  economizer  be  partially  emptied  of  water.  The  amount  of 
steam  formed  is  about  the  same  quantity  as  that  of  the  water 
discharged.  This  caution  should  be  observed,  otherwise  water 
hammer  may  occur. 

A  pressure  gage  located  near  the  blow-off  will  show  when  the 
pump  has  maintained  the  pressure.  In  closing  the  valve  the  gage 
will  show  whether  or  not  the  pump  slows  down  to  prevent  excessive 
pressure  in  the  economizer.  Fig.  203  shows  an  economizer  with 
the  feed  entering,  in  one  case  at  the  end  of  the  upper  manifold, 
then  passing  through  two  sections  to  the  lower  manifold.  It  also 
shows  in  dotted  lines  the  usual  and  more  correct  form,  having  the 
feed  enter  at  one  end  of  the  lower  manifold,  with  the  blow-off  at 
the  other  end.  As  the  lower  portion  of  the  economizer  is  much 
cooler  than  the  tubes  and  upper  headers,  it  is  much  better  that 
the  cool  water  enter  at  the  bottom,  thereby  avoiding  the  extreme 
changes  in  temperature  which  cause  trouble. 

Class  S4  —  Blow-Off  Branches  from  Heaters,  Purifiers,  Etc. 
A  closed  heater  requires  a  blow-off  at  the  lowest  point  in  the  water 
space,  the  precipitation  being  in  the  form  of  mud  and  not  likely 
to  injure  the  valve.  However,  it  is  best  to  use  two  blow-off  valves, 
as  with  boilers.  If  only  one  valve  were  used  it  would  be  necessary 
to  have  a  wash-out  tee  next  to  the  heater.  Live  steam  purifiers 
should  have  similar  protection  and  means  for  washing  out.  The 
washings  from  any  station  device  should  be  in  plain  view,  so  that 
the  operator  can  see  exactly  what  is  being  accomplished. 


BLOW-OFF   PIPING.  455 

It  is  essential  that  the  station  operator  be  able  to  know  what  he 
is  doing  and  be  able  to  protect  himself  against  accident.  Double 
blow-off  valves  and  sewer  wash-outs  are  necessary  to  care  for  these 
requirements.  Small  economies  effected  by  saving  a  few  valves 
will  be  insignificant  compared  to  the  payment  of  damages  in  cases 
of  injury. 

Class  S5  —  Blow-Offs  from  Steam  Traps  and  Bleeders.  Steam 
trap  drips  which  contain  grease  should  be  discharged  through  a 
blow-off,  if  practicable,  to  avoid  vapor  in  the  sewer.  Traps 
discharging  water  from  the  intermediate  receiver  discharge  at 
low  pressures  and  should  be  provided  with  check  valves  to  prevent 
the  possibility  of  water  backing  through  them  if  a  trap  were  open 
while  a  boiler  was  being  blown. 

Check  valves  in  blow-off  lines  are  liable  to  cause  trouble,  first 
appearing,  with  possibly  destructive  results,  when  water  reaches 
a  low-pressure  cylinder.  Bleeders  for  removing  condensation 
from  boilers  and  engine  branches  should  be  run  to  the  heaters, 
if  such  connections  can  be  made  without  piping  complications. 

Steam  traps  either  are  furnished  with  gage  glasses,  or  have 
tapped  openings  for  them.  As  it  is  impossible  to  maintain  a  glass 
where  the  temperature  is  constantly  changing,  a  better  plan  is  to 
arrange  for  an  audible  discharge  from  the  trap.  The  operator, 
becoming  accustomed  to  this 
sound,  is  warned  immediately 
upon  its  ceasing.  Fig.  367 
(85-1)  shows  a  trap  having 
two  different  sound-making 
devices  in  its  discharge.  One 
has  an  air  chamber  which 

fills  with  vapor  and  air  after  the  FIG.  367  (85-1). 

trap  has  discharged.  When 
the  trap  again  discharges  the  vapor  and  air  are  blown  out,  sounding 
the  whistle.  The  other  device  consists  of  a  vibrator  placed  in  the 
path  of  the  discharge,  the  impact  of  the  water  causing  a  vibration 
similar  to  that  of  a  tuning  fork. 

Bleeders  are  generally  small,  and  if  much  used  should  have 
two  valves  placed  together,  the  valve  next  to  the  pressure  being 
used  as  a  controlling  valve,  the  second  one  only  as  a  stop  valve. 

Class  S6  —  Blow-Off  Tanks.  A  blow-off  tank  is  intended  to 
protect  the  sewer  against  high  temperature  water  and  steam. 


456 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


Its  use  is  compelled  by  ordinance  in  many  cities.  That  these 
tanks  are  often  made  and  used  in  a  manner  unfit  for  the  service 
is  shown  by  steam  escaping  trom  many  sewer  gratings  in  the 
streets.  The  problem  is  far  from  simple,  and  the  arrangements 
necessary  to  overcome  the  existence  of  vapor  and  hot  water  in 
sewers  are  very  extensive. 

With  a  blow-off  tank  as  sometimes  designed  the  steam  is  allowed 
to  escape  through  a  vent  pipe  carried  to  a  high  elevation.  This 
tank  is  all  that  is  provided  in  many  cases  to  care  for  the  boiler 
blow-off,  and  the  vent  often  is  too  small,  not  only  allowing  steam 
to  be  carried  into  the  sewers,  but,  since  it  also  fails  to  relieve 
the  pressure,  allowing  water  to  be  discharged  through  the  vent. 
High  temperature  water  from  the  boiler  will  expand  to  about 
200  cu.  ft.  of  steam  for  each  cubic  foot  of  water  discharged. 

The  exhaust  can  be  carried  off  with  a  large  vapor  pipe  run  to  a 
high  elevation  so  that  the  air  will  flow  into  the  sewer  openings  and 
out  through  the  vent  pipe,  as  shown  in  Fig. 
368  (S6-i).  As  shown,  the  discharge  from 
the  blow-off  main  is  pointed  upward  to  break 
up  the  boiler  water  and  allow  the  greatest 
possible  amount  of  steam  to  escape,  this  being 
the  only  point  for  discharging  the  heat  from 
the  water  other  than  into  the  sewer.  The 

baffle  in  the 
blow-off  sys- 
tem prevents 
the  hot  water 
from  going 
directly  to  the 
sewer.  The 
vent  pipe 


should  bc 
large,   say    18 

to  24  in.  in  diameter,  and  may  be  made  of  materials  similar  to 
those  used  in  a  smokestack.  The  joints  should  be  lapped  so  that 
the  water  will  run  from  the  outside  to  the  inside.  A  circulation 
down  the  sewer  manhole,  through  the  main  sewer  and  blow-off 
to  the  cistern,  then  up  the  vent  pipe,  would  prevent  leakage  at  the 
sewer  manholes.  In  such  blow-off  equipments  the  sewer  leading 
from  the  cistern  to  the  main  sewer  should  be  large,  thus  enabling 


BLOW-dFF  PIPING. 


457 


air  and  vapor  to  pass  the  water  which  would  be  discharged  into 
the  sewer. 

The  heat  units  in  the  blow-off  water  are  ordinarily  wasted,  but 
it  would  be  practicable  to  blow  off  into  a  settling  chamber,  thus 
allowing  the  impurities  and  the  scale  to  settle  and  then  returning 
the  water  to  the  boilers.  As  the  blowing  off  of  a  boiler  takes  place, 
ordinarily,  but  once  or  twice  a  day,  the  gain  by  thus  saving  the 
water  blown  from  the  boilers  would  necessarily  be  slight. 

The  blow-off  cistern  shown  in  Fig.  369  (86-2)  is  located  at  about 
50  ft.  from  the  building  and  has  an  open  grating  to  permit  the  escape 
of  steam.  This  cistern  is  constructed  as  a  storage  for  the  blow-off 


^Open/ngfl  SqpJMnf' 

FIG.  369  (86-2). 


of  water  with  its  discharge  valves  set  so  that  the  rate  of  discharge 
into  the  sewer  will  be  small.  Such  a  cistern  should  have  a  storage 
capacity  of  not  less  than  70  cu.  ft.  The  pipe  from  the  building  to 
the  cistern  should  be  inclosed  in  a  tile  sewer  pipe,  which  will 
permit  its  removal.  The  opening,  A,  in  the  building  wall  should 
have  a  clear  space  in  front  of  it  to  permit  removing  a  full  length 
of  pipe,  thus  allowing  the  entire  blow-off  main  to  be  removed. 
The  slip-joint  at  the  cistern  end  would  afford  a  ready  means  for 
closing  the  opening  in  the  cistern,  at  the  same  time  permitting 
free  movement  of  the  pipe  line  in  the  boiler  room.  The  regulating 
valve  in  the  cistern  should  not  be  over  2  J  in.  in  diameter  and  should 
be  of  brass.  An  old  valve  can  be  used  for  this  purpose,  as  it  will 
neither  be  under  pressure  nor  closed  tightly.  The  check  valve 
in  the  boiler  room  should  not  be  less  than  one  inch  in  opening,  as 
the  discharge  end  of  the  blow-off  will  be  under  water  and  any 
vacuum  formed  in  the  blow-off  main  should  be  broken  without 
drawing  cistern  water  back  into  the  line.  The  blow-off  main 
back  of  the  boilers  should  be  located  above  the  high-water  level 
of  the  cistern  to  avoid  water  hammer. 


CHAPTER    XXIX. 
GREASE    SEWERS. 

Class  Tl  —  Grease  Sewer  Main.  Grease  sewers  are  not  generally 
dignified  as  systems;  in  fact,  they  are  usually  given  but  little  con- 
sideration. Instead  of  well  planned  systems  being  installed,  one 
finds  that  greasy  discharges  are  run  into  the  blow-off.  Fig.  46 
shows  in  a  general  way  the  cold  sewers  and  the  hot  sewers,  each  as 
a  separate  line.  There  are  many  greasy  wastes  in  a  plant  that 
should  not  be  discharged  into  the  regular  gravity  sewers.  The 
grease  sewers  should  be  constructed  similarly  to  the  blow-off 
systems,  but  if  free  from  pressure  they  may  be  built  of  iron  soil 
pipe  with  calked  lead  joints  and  run  underground.  It  is  partly 
due  to  the  fact  that  these  greasy  drips  ruin  cement  work  that 
separate  lines  are  necessary. 

The  various  locations  of  hot  sewer  inlets  make  it  quite  impossible 
to  use  standard  wrought  pipe  and  to  place  the  grease  lines  above 
ground.  In  Fig.  46  the  pipe  is  shown  resting  on  loose  packing 


FIG.  370  (Ti-i). 

sand  and  provided  with  a  sleeve  through  the  cement  floor,  which 
latter  detail  allows  for  the  movement  of  the  pipe.  If  screwed 
wrought-iron  pipe  were  used  for  the  hot  sewer,  it  would  last 
indefinitely  if  the  sewer  were  not  subjected  to  pressure  in  blowing 
off,  as  oil  would  also  be  discharged  through  the  blow-off  cistern. 
Fig.  370  (Ti-i)  shows  good  construction  for  a  separate  blow-off 
or  grease  separating  tank  with  a  small  vapor  pipe.  As  built 

458 


GREASE  SEWERS.  459 

the  grease  would  remain  in  this  tank  until  removed,  and  as  a 
comparatively  large  amount  of  oily  drips  would  reach  this  tank 
a  considerable  amount  of  grease  would  be  collected.  The  drip 
line  is  carried  through  a  tile  pipe,  the  purpose  of  which  is  to  hold 
the  soil  away  from  the  line.  Each  branch  of  the  drip  line  should 
have  a  tight  connection  at  its  upper  end  to  prevent  steam  from 
escaping.  The  drip  line  should  run  down  into  the  tank  suffi- 
ciently far  to  prevent  much  agitation  of  the  grease  at  the  top. 
The  discharge  is  shown  with  a  tee  at  the  upper  opening,  thus 
preventing  the  contents  of  the  tank  from  siphoning  down  to  the 
sewer  level.  The  drop  pipe  allows  water  to  be  discharged  with- 
out losing  the  grease. 

Some  form  of  tin  pump  might  be  used  to  remove  the  grease, 
which  could  be  used  for  various  purposes.  In  considering  the 
saving  of  oil  and  grease,  no  arrangements  should  be  made  to  dis- 
charge this  kind  of  grease  into  an  oiling  system,  as  it  is  wholly 
unfit  for  journals;  in  fact,  an  oiling  system  to  work  most  satis- 
factorily must  be  able  to  rid  itself  of  this  class  of  grease  if  once 
it  has  taken  it  up.  It  will  be  necessary  to  give  the  line  consider- 
able pitch  to  avoid  the  possibility  of  drawing  back  water  standing 
in  the  line. 

Class  T2  —  Grease  Sewer  from  Engines.  Practically  all  of  the 
cylinder  oil  that  gets  into  the  oiling  system  is  discharged  from 
the  piston  and  valve  rod  stuffing  boxes.  Some  engine  builders 
provide  a  grease  compartment  between  the  front  head  of  the 
cylinder  and  the  cross-head  guide,  with  a  stuffing  box  to  isolate 
this  compartment.  If  pockets  to  catch  oil  drips  are  also  provided 
in  valve  bonnets  then  little  cylinder  oil  will  be  discharged  into  the 
oiling  system.  Ordinarily  these  drips  are  run  to  the  sewer,  but 
with  the  grease  sewer  system,  as  shown  in  Fig.  370,  much  oil  can 
be  saved  and  used.  Ordinarily  a  pocket  can  be  put  on  the  front 
head  to  catch  drips  from  the  piston  rod,  as  shown  in  Fig.  371 

(Ta-l). 

If  there  are  bleeders  at  the  ends  of  the  cylinders,  also  from  the 
steam  chest,  it  will  be  found  safer  to  discharge  them  into  the 
exhaust  at  the  highest  point  possible  rather  than  into  the  grease 
sewer.  Then  the  drain  from  the  exhaust  line  or  receiver  could 
be  run  to  the  grease  sewer.  If  a  trap  is  used  to  carry  away  drips 
from  the  intermediate  receiver,  it  should  discharge  into  the  grease 
sewer,  and  if  the  line  is  well  pitched  there  will  be  but  little  water 


460 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


for  it  to  suck  back  in  case  pressure  on  the  receiver  falls  below 
that  of  the  atmosphere.  To  further  protect  engines  against  water 
being  drawn  in,  it  is  advisable  to  place  a  check  valve  at  a  tee  in 
the  trap  discharge,  the  check  falling  closed,  but  free  to  open  when 
under  a  partial  vacuum.  The  exhaust  that  runs  to  the  condenser 


FIG.  371  (Ta-i). 


FIG.  372  (T3-i). 


should  also  have  a  check  in  its  drip  line,  but  the  reverse  of  that 
for  the  intermediate  receiver  trap.  The  exhaust  should  close 
with  a  vacuum  and  be  open  when  under  pressure. 

These  different  oily  steam  drip  lines  are  shown,  in  Fig.  325, 
as  running  to  a  drip  tank.  The  drain  from  this  tank  is  run  to  a 
grease  sewer.  A  drip  tank  should  be  of  generous  capacity,  say, 
for  a  2,ooo-hp.  engine,  12  in.  diameter  by  4  ft.  high.  The  vent 
from  the  top  to  the  atmospheric  pipe  should  be  amply -large  to 
discharge  the  steam  blown  into  it,  say  about  2}  in.  in  diameter. 
With  such  a  drip  tank  but  one  underground  connection  to  the 
grease  sewer  will  be  required. 

Class  T3  —  Grease  Sewer  from  Pumps.  All  pumps  should  be 
provided  with  a  lipped  cast-iron  pan  the  full  size  of  the  pump. 
This  pan  should  have  raised  spots  for  the  pump  feet  and  a 
strainer  for  the  pipe  discharge.  The  pan  shown  in  Fig.  372 
(T3-i)  is  simple  in  design  and  effective. .  The  tops  of  the  bosses 
are  set  level  and  the  pan  pitched  toward  the  drain.  A  strainer 
should  be  placed  over  the  drip  opening. 

A  possible  error  in  pan  construction  is  to  place  the  anchor 
rods  close  to  the  edge  of  the  pan,  thus  making  a  good  job  of 
masonry  of  either  brick  or  concrete  impossible,  since  there  will 
be  too  little  material  outside  of  the  rod.  The  rod  bosses  should 


GREASE  SEWERS.  461 

be  projected  from  the  pump  feet  bosses,  making  the  fewest  possible 
corners  to  wipe  around.  Another  error  is  to  use  these  anchor 
rods  for  securing  the  pump  to  the  pan.  The  anchor  rods  are  more 
or  less  elastic  and  do  not  hold  the  pump  firmly.  To  obtain  a 
rigid  job  the  pump  should  be  anchored  to  the  pan  and  the  pan  then 
anchored  to  the  foundation.  The  holes,  B,  are  quite  essential 
for  securing  a  good  job  of  grouting  when  the  pan  is  placed  on  the 
foundation.  The  lip  around  the  edge  of  the  pan  should  not  be 
less  than  ij  in.  high.  The  top  of  the  pump  bosses  and  the  outer 
rim  also  should  be  on  one  level  to  prevent  oil  from  getting  into  the 
foundation. 

The  drain  valve,  C,  should  be  used  if  the  pan  drips  are  run  into 
the  grease  sewer.  The  tee,  D,  is  to  connect  the  blow-offs  from 
the  steam  cylinder  as  shown  in  Fig.  324.  The  pan  drips  will 
carry  away  much  grease  and  oil  which  can  ordinarily  be  discharged 
to  the  grease  sewer  by  leaving  the  valve,  C,  slightly  open.  The 
drain  from  the  exhaust  pipe  may  also  be  connected  to  opening,  D. 

Class  T4  —  Grease  Sewer  from  Grease  Extractors.  If  there  is 
a  grease  extractor  in  the  exhaust  line,  then  the  drips  should  be 
discharged  directly  to  the  grease  sewer;  but  if  considerable  back 
pressure  is  carried,  then  a  trap  such  as  shown  in  Figs.  161  and  162 
should  be  used  to  keep  the  steam  from  blowing  through  to  the 
grease  sewer.  Any  drains  taken  from  the  bottom  of  exhaust 
lines  should  be  run  to  this  sewer.  If  a  grease  extractor  is  used  in 
a  vacuum  line,  then  the  drips  should  be  run  to  a  vacuum  trap  and 
this  trap  should  discharge  into  the  grease  sewer.  If  the  heater 
overflow  is  used  to  discharge  oil  from  the  surface,  then  this  dis- 
charge should  also  be  run  to  the  grease  sewer.  It  is  poor  station 
management,  after  the  grease  has  been  caught,  to  discharge  it 
into  the  regular  sewer,  thus  not  only  losing  this  valuable  material 
but  injuring  the  sewers  as  well. 

Class  T5  — Grease  Sewers  to  Precipitating  Tanks.  The  pre- 
cipitating tanks  are  used  to  remove  from  the  engine  oil  system 
such  oil  and  grease  as  may  be  found  in  the  grease  trap  shown  in 
Fig.  370.  If  considerable  light  oil  reaches  this  trap  it  also  should 
be  discharged  into  the  precipitating  tank.  After  heavy  oil  has 
stood  in  the  precipitating  tank,  it  becomes  of  a  more  uniform 
grade  and  can  be  drawn  off.  This  detail  requires  some  kind  of  a 
pump  that  can  be  started  and  run  until  the  grease  has  been  removed 
from  the  grease  trap. 


CHAPTER    XXX. 


TILE   SEWERS. 

Class  Ul  —  Tile  Sewers  —  Main.     Power  plant  sewers  fulfill  so 
many  different  services  that  it  may  be  found  better  not  to  join  them 
all.     The  wash  water  and  rain  water  sewers  can  be  joined,  but  the 
grease  discharges  and  soil  pipe  wastes  should  be  kept  independent. 
In  a  condensing  plant  the  wash  and  rain  water  can 
be  run  into  the  discharge  waterway.     The  sewers 
under  a  high  head  should  not  be  connected  with 
those  of  low  head  or  they  will  flood  the  basement 
floors.     The  requirements  of  each  sen- ice  must  deter- 
mine which  branches  shall  be  united  into  one  main. 
If  grease  and  water  of  extremely  high  temperature 
are  kept  out  of  the  sewers  the  main  may  be  built 
of  the  pipe  with  cement  joints.     Oil  carried  in  a 
drain  serves  to  preserve  the  iron  pipe,  but  it  will 
destroy  the  cement  joints  of  tile  pipe.     The  choice 
Fio.373(U2-i).  of  material   for  sewers  depends  upon   how   much 
grease  is  to  be  handled  and  how  much  water  will 
flow  with  the  grease. 

Class  U2  —  Tile  Sewers  from  Roof  Conductors.  The  main 
branches  that  carry  the  roof  water  are  subject  during  a  heavy  rain 
to  sufficient  pressure  to  raise  water  out  of  the  basement  catch  basin. 
If  possible  the  roof  should  be  divided  so  that  a  small  surface  will 
drain  into  the  closet  sewers  and  flush  out  the  soil  pipe. 

The  conductors  from  high  or  hot  roofs  should  be  run  on  the 
inside  of  the  building  in  a  warm  place.  The  heat  of  the  roof 
often  will  melt  the  snow  in  cold  weather  and  therefore  the  conductor 
should  be  protected  from  low  temperatures.  Fig.  373  (U2-i) 
shows  a  conductor  arranged  for  flashing  joined  to  a  section  of  cop- 
per spout  which  is  run  down  into  the  iron  conductor.  The  iron 
conductor  may  be  of  light  ca^t-iron  soil  pipe  with  calked  joints  and 
a  cast-iron  Y  built  into  the  wall  to  receive  the  lower  end  of  the 
down  spout.  The  different  pipe  sections  should  have  substantial 

46? 


TILE  SEWERS.  463 

wall  anchors,  and  the  Y  at  the  bottom  should  have  a  cap  with  a 
cemented  joint,  so  that  it  can  be  removed  if  it  becomes  necessary 
to  clean  out  the  conductor  or  branch  to  the  sewer. 

The  outside  sewer  connections  should  be  of  tile  pipe,  as  there 
is  no  advantage  in  the  use  of  metal  pipes  unless  they  pass  under 
walls  or  foundations.  In  establishing  the  depth  at  which  sewers 
are  to  be  placed  it  must  be  remembered  that  water  may  pass  from 
the  roof,  even  though  the  temperature  of  the  ground  be  very  low. 
Also  the  heat  of  the  power  plant  and  water  passing  in  sewers  raises 
the  temperature.  Waterworks  lines  are  generally  located  5  ft. 
below  the  surface.  Sewers  close  to  the  buildings  laid  3  ft.  below  the 
surface  would  be  quite  as  safe  as  the  water  lines.  If  the  plant  is 
large  it  may  be  necessary  to  use  large  sewers  with  a  slight  pitch, 
so  that  the  highest  connection  will  not  be  less  than  3  ft.  from  the 
ground  surface  and  the  discharge  of  sewer  above  normal  water 
level. 

It  is  not  necessary  that  the  entire  sewer  system  discharging  to  the 
river  lie  above  extreme  high  water.  As  high  water  conditions 
are  of  short  duration  water  may  be  allowed  to  back  into  the  main 
as  long  as  it  does  not  overflow  any  of  the  floor  drains.  The  fall, 
however,  must  be  given  careful  consideration  if  paper  is  to  be  dis- 
charged into  the  sewer,  as  a  slight  obstruction  where  the  flow  is 
very  slow  will  cause  the  paper  to  block  the  line  completely.  The 
sewers  from  soil  pipes  should  not  be  retarded  by  water  rising  and 
filling  the  discharge  end  of  the  sewer. 

Class  U3  —  Tile  Sewers  from  Plumbing  Fixtures.  Sewers  from 
the  lavatories  are  generally  difficult  to  lay  out.  If  the  condenser 
discharge  waterway  is  built  of  concrete  then  a  separate  soil  pipe 
may  be  carried  in  the  concrete,  as  shown  in  Fig.  374  (113-1). 
Sewer  tile  or  a  collapsible  wood  frame  could  be  used  to  form  the 
soil  pipe  opening.  Probably  it  will  be  found  cheaper  to  lay  the 
soil  pipe  in  the  fill  over  the  concrete;  or  if  this  brings  it  too  close 
to  the  surface  of  the  ground  it  might  be  laid  alongside,  as  dotted 
at  A,  in  Fig.  374.  This  separate  sewer  pipe  should  extend  beyond 
the  blow-off  cistern  in  the  waterway,  otherwise  it  will  contaminate 
the  condenser  discharge  waterways.  By  this  method  there  will 
be  no  fumes  rising  from  the  waterway  into  the  station. 

The  lavatory  should  be  located  in  the  basement  at  the  outside 
wall,  as  shown  in  Fig.  375  (113-2).  If  the  conductor  should  be  at 
a  corner,  as  A,  then  it  can  be  run  back  along  the  wall,  or  the  sewer 


464 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


can  make  a  loop  to  include  the  conductor.  Plumbing  fixtures 
should  be  so  arranged  that  the  water  from  the  wash  basins, 
shower  bath  and  a  small  roof  conductor  is  made  to  pass  through 
the  line  that  leads  from  the  closets.  This  will  insure  that  the 
line  will  be  well  flushed. 


FIG.  374  (U3-i). 


FIG.  375  (U3-2). 


Another  detail  in  connection  with  the  sewers  from  water  closets 
is  that  as  they  are  liable  to  become  blocked  they  should  not  be 
run  under  engine  foundations,  boiler  rooms,  or  with  many  branches 
and  bends  in  places  where  they  cannot  readily  be  taken  up. 


FIG.  376  (U4-i). 


FIG.  377  (U4-2). 


Class  U4  — Tile  Sewers  from  Floor  Drains.  The  boiler  room 
and  basement  floors  should  be  so  arranged  that  they  can  be  cleaned 
with  a  hose.  To  do  this  satisfactorily  it  is  necessary  to  have  a 
large  number  of  catch  basins  and  ample  pitch  to  the  floor. 
Fig-  376  (U4-i)  shows  a  floor  with  the  pitch  run  to  suit  the  catch 
basins.  The  pitch  boards  should  be  set  on  the  lines  A  and 
the  gutter  strips  placed  at  B,  both  strips  to  be  removed  after  the 
concrete  and  cement  top  is  in  place,  previous  to  finishing  the 


TILE  SEWERS.  465 

surface.  The  slots,  A,  are  to  be  filled  with  cement  and  sand. 
The  gutters,  B,  should  be  about  two  inches  deep,  with  the  corners 
well  rounded.  The  pitch  of  the  gutters  and  floors  should  be 
about  0.25  in.  to  the  foot,  which  makes  it  necessary  to  place  the 
top  of  the  catch  basin  below  the  surrounding  floor  level,  as  shown 
in  Fig.  377  (114-2).  The  distance,  A,  in  many  cases  is  as  much 
as  four  inches,  and  with  the  catch  basin  set  low  a  bad  hole  in  the 
floor  is  made.  If  an  extension  side  drainer  is  used  as  shown,  then 
the  grating  can  be  placed  in  the  top  and  the  floor  concrete  floated 
to  the  top  of  this  extension  piece,  thus  making  the  floor  level. 
Water  will  discharge  between  the  fingers  at  the  side  of  the  extension 
piece  and  above  the  fine  sieve  grating.  The  catch  basin  has  a  side 
outlet,  and  no  trap.  This  allows  the  connection  to  the  basin 
to  lie  high  and  also  be  entered  easily  with  a  rod  or  hose  when 
being  flushed. 

These  floor  drains  should  not  empty  into  the  lavatory  sewers, 
unless  a  trap  is  used,  with  means  available  for  cleaning  out  sand 
or  other  material  that  may  be  washed  in  from  the  floor.  If  the 
floor  drains  in  the  basement  are  on  practically  the  same  level  as 
the  sewer,  it  may  be  necessary  to  use  a  non -return  sewer  check 
valve,  as  shown  in  Fig.  378  (114-3).  The  check  discharges 
into  a  cistern  which  has  its  sides  carried  above  the  floor  to  prevent 
overflowing  in  case  of  the  sewer  running  full  under  a  slight  back 
pressure.  This  check  is  always  open  to  inspection,  and  should  it 
fail  to  close  it  might  be  closed  by  hand.  Floor  drain  outlets 
should  be  placed  in  this  well  just  above  the  bottom  of  the  main 
sewer,  so  that  the  well  will  drain  itself  as  soon  as  the  sewer  becomes 
empty. 

Sewer  checks  are  so  made  that'they  can  be  placed  in  a  line 
outside  of  the  well,  but  when  so  placed  their  operation  cannot  be 
observed.  A  trap  similar  to  that  in  Fig.  378  would  be  suitable 
for  use  if  the  floor  drains  discharged  into  the  lavatory  sewer, 
the  check  being  omitted  and  some  form  of  manhole  plate  and 
frame  placed  at  the  floor  line. 

Wherever  ashes  are  wet  down  in  front  of  boilers  a  cistern  is  use- 
ful if  located  in  a  central  position  so  that  the  different  catch  basins 
may  be  separately  drained  into  it.  In  a  large  plant  it  may  be 
necessary  to  use  a  number  of  these  cisterns,  having  a  small  well 
at  each  sewer  grating  and  carrying  the  discharge  from  one  to  the 
next,  and  so  on,  as  shown  in  Fig.  379  (1/4-4),  with  the  iron 


466 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


gratings  carried  in  a  square  frame.  The  runs  from  basin  to  basin 
should  be  short  and  straight.  The  last  cistern  in  the  series  should 
be  much  larger  and  deeper  than  the  others,  to  protect  the  sewer 
from  that  point  on.  If  necessary,  a  fine  wire  cylindrical  screen 
can  be  placed  at  the  last  discharge. 


FIG.  378  (U4-3). 


FIG.  379  (U4-4). 


If  the  engine  room  floor  is  of  cement  or  tile  the  drain  would  be  over 
a  level  surface  because  in  washing  the  floor  but  little  water  would  be 
used.  The  drains  then  might  be  small  and  located  under  the  hose 
valves.  A  small  catch  basin  should  be  placed  below  the  surface 


Plan  Vie* 
FIG.  380  (U4-s).  FIG.  381  (U4-6). 

of  the  floor,  as  shown  in  Fig.  380  (114-5),  with  the  water  connec- 
tion as  passing  through  a  raised  boss  in  the  small  drip  sink.  This 
boss  prevents  the  drips  from  running  down  the  water  pipe.  If  the 
floor  is  marble  or  tile  then  the  body  of  the  sink  should  be  galvanized 


TILE   SEWERS.  467 

to  prevent  its  rusting  and  staining  the  floor.  The  shape  and  size 
of  these  sinks  should  correspond  with  the  size  of  the  tile  to  be  used. 
The  water  valve  should  be  attached  to  a  45 -degree  elbow  so  that 
the  hand  wheel  will  clear  the  wall. 

In  many  plants  where  the  basements  have  practically  no  fall, 
an  open  sewer  can  be  used.  Fig.  381  (U4-6)  shows  two  open 
sewers,  one  covered  with  a  grating  so  it  may  be  stepped  on,  and 
the  other  next  to  a  wall  and  without  a  cover.  The  wooden  form 
as  shown  in  the  uncovered  sewer  is  required  for  placing  the  con- 
crete flooring.  An  advantage  of  this  type  of  sewer  is  that  but 
little  pitch  is  required.  Tile  sewers  should  not  be  used  if  the  pitch 
be  less  than  0.25  in.  per  ft. 

Class  U5  —  Tile  Sewers  from  Ash  Wetting  Floor.  The  catch 
basin  which  receives  ash  laden  water  should  be  so  designed  that 
the  tendency  will  be  for  heavy  cinders  to  fall  away  from  the  sewer 
pipe  discharges  while  fine  particles  rise  and  are  carried  by  the  slow 
movement  of  water  in  the  catch  basin  to  the  more  rapid  current 
in  the  sewer  pipe.  These  requirements  are  well  provided  for  by 
the  catch  basin  shown  in  Fig.  379. 

Ordinary  sewer  details  as  employed  for  carrying  away  water 
will  not  handle  ashes  without  becoming  blocked.  A  sufficient 
flow  to  carry  away  the  precipitation  is  impossible.  Heavy  mate- 
rials such  as  ashes  should  be  stored  in  the  sewerage  system  where 
they  can  be  reached  and  not  forced  into  the  main  line. 

Class  U6  —  Tile  Sewers  from  Boiler  Washouts.  Tile  sewers 
leading  from  boiler  washouts  are  shown  in  Figs.  365  and  366. 
These  have  catch  basins  similar  to  that  shown  in  Fig.  376.  If 
water  and  scale  were  discharged  on  to  a  floor  or  the  bottom  of 
pit  as  shown  in  Fig.  366,  and  if  the  drain  from  this  discharge 
were  allowed  to  flow  over  a  wide  surface  to  a  sewer  a  considerable 
distance  away,  then  the  velocity  of  the  water  passing  over  the 
floor  would  be  less  than  through  the  sewer,  and  the  fine  particles 
carried  by  the  slow-moving  water  would  not  be  carried  with 
sufficient  force  to  pass  them  through  the  sewers. 

An  illustration  of  this  principle  is  shown  in  Fig.  382  (U6-i). 
The  middle  boiler  is  shown  discharging  water  and  scale  into  the 
pit,  the  heavy  particles  falling  and  water  overflowing  through  the 
blow-off  trenches  at  A.  In  operation  the  catch  basin,  by  is  shut 
off  before  the  workman  begins  to  clean  the  boiler.  Thus  the  pit 
becomes  a  precipitation  chamber.  The  light  material  rises  to  the 


468 


STEAM   POWER  PLANT  PIPING  SYSTEMS. 


surface  and  passes  the  overflow,  A,  reaching  the  sewer  in  a  flow 
of  high  velocity.  The  catch  basins  here  shown  have  the  same 
design  as  those  shown  in  Fig.  379.  If  the  cleaning  of  the  catch 
basin  shown  in  Fig.  379  is  neglected,  it  fills  up  to  the  level  of  the 
discharge  sewer  and  the  particles  will  work  into  the  main  line. 


FIG.  382  (U6-i). 

Another  form  of  catch  basin,  and  one  that  shuts  off  the  water 
discharge  whenever  it  becomes  choked  with  deposits,  is  shown 
in  Fig.  383  (U6-2).  This  design  is  similar  to  that  shown  in 
Fig.  379,  but  it  has  a  central  cone-shaped  feeder  which  will  become 
choked  when  the  lower  end  comes  in  contact  with  the  deposits 


FIG.  383  (U6-2). 


FIG.  384  (Uy-i). 


at  the  bottom  of  the  catch  basin.  The  basin  shown  in  Fig.  383 
can  be  used  as  shown  in  Figs.  379  and  382,  with  the  sewer  passing 
through  it,  or  all  the  branches  can  be  run  to  a  sewer  line  with 
Y  fittings,  thus  offering  little  or  no  chance  for  anything  getting 
into  the  line  that  will  not  pass  through  it.  The  cone-shaped  feeder 
is  similar  in  operation  to  the  coal  feeders  used  in  hard  coal  stoves, 
the  amount  of  material  in  the  cone  having  no  effect  in  raising  the 
deposits  in  the  cistern  above  the  bottom  of  the  cone.  The  inside 


TILE   SEWERS.  469 

grating  has  a  handle  and  can  be  taken  out  quickly  to  allow  the 
removal  of  cinders. 

Class  U7  —  Tile  Sewers  from  Economizers  and  Heaters.  Since 
loose  scale  is  discharged  with  the  wash  water,  the  sewer  arrange- 
ment for  economizers  and  heaters  should  be  much  the  same  as  for 
boilers.  Rather  than  build  complicated  catch  basins  to  keep 
scale  out  of  sewers,  it  may  be  found  cheaper  to  use  some  portable 
separating  device  which  may  be  placed  at  any  washout  outlet  and 
the  discharge  from  this  separator  allowed  to  flow  to  a  simple  form 
of  catch  basin.  If  the  washout  outlets  are  two  feet  or  more  above 
the  floor  line,  then  it  will  be  possible  to  have  such  a  separator 
mounted  on  wheels  so  that  the  scale  collected  can  be  removed 
to  a  convenient  place  for  dumping.  The  simplest  device  for  this 
purpose,  however,  would  be  a  long,  narrow  box,  say  3  ft.  wide, 
12  in.  high  and  8  ft.  long,  designed  to  allow  the  water  to  overflow 
its  edges.  Any  material  washed  away  with  the  water  would  be 
carried  through  the  sewers.  This  box  should  be  made  of  metal, 
and  if  made  of  No.  12  plate  could  be  readily  handled,  if  not 
mounted  on  wheels.  A  practical  arrangement  is  shown  in  Fig.  384 
(U7-i).  The  discharge  from  the  washout  which  drops  on  to  the 
pitched  floor  will  run  to  an  open  drain  connected  to  a  catch 
basin. 

Class  U8  —  Tile  Sewers  from  Blow-off  and  Grease  Tank.  The 
sewer  from  the  blow-off  tank  should  be  arranged  as  shown  in 
Fig.  369,  so  that  steam  may  escape  and  the  water  be  discharged 
under  control  of  a  valve.  Floor  drains  from  catch  basins,  as 
shown  in  Figs.  377  and  379,  should  not  be  run  into  a  line  that 
carries  the  blow-off  water  unless  a  trap  is  used  to  prevent  the 
steam  from  passing  back  into  the  building. 

Class  U9  —  Tile  Sewers  from  Pumps.  Steam  cylinder  and 
pan  drips  should  be  led  to  a  grease  trap  through  the  grease  sewer, 
as  shown  in  Fig.  379.  The  catch  basins  can  then  be  used  as 
floor  drains.  If  two  pumps  stand  close  together  it  is  generally 
possible  to  make  one  catch  basin  serve  both.  The  relief  valves 
of  such  pumps  should  be  piped  to  a  point  about  three  inches  above 
the  grating  of  the  catch  basin.  Pumps  having  outside  packed 
plungers  should  have  a  pan,  as  shown  in  Fig.  372.  Instead  of 
water  and  oil  being  allowed  to  drip  into  the  pan  and  mix,  there 
should  be  a  dividing  partition,  the  drips  from  the  water  end 
discharging  into  the  catch  basin,  and  the  drips  from  the  steam 


470  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

end  running  into  the  grease  sewer.  This  division  allows  the 
water  drips  to  discharge  at  all  times. 

Class  U10  —  Tile  Sewers  from  Filters.  The  cold  water  niters 
can  be  drained  to  the  sewer  if  the  waste  water  is  discharged  into  a 
well  or  basin  open  to  the  air.  A  sealed  connection  should  not  be 
used  if  the  discharge  is  under  pressure,  because  a  pressure  of  one 
or  two  pounds  would  be  sufficient  to  cause  damage  to  the  ordinary 
sewer.  If  the  filter  is  to  discharge  under  pressure,  then  it  should 
be  connected  to  the  blow-off  system.  Oil  filters  and  tanks  should 
discharge  their  grease,  together  with  the  hot  wash  water,  into  the 
grease  sewer.  The  automatic  water  discharge  shown  in  Fig.  350 
should  discharge  to  the  tile  sewer.  There  will  be  no  grease  in 
this  water  and  the  connection  can  be  open  to  the  atmosphere  at 
all  times. 

The  washings  from  the  precipitating  tank,  Fig.  351,  should  also 
be  run  to  the  grease  sewer.  It  may  seem  at  first  that  it  is  poor 
operation  to  discharge  the  contents  of  a  grease  trap  into  a  precipi- 
tation tank,  then  wash  the  grease  that  hangs  to  the  side  of  the 
precipitation  tank  back  into  the  grease  trap.  This  clinging 
grease,  however,  is  no  more  refuse  than  that  which  is  drawn  off 
to  be  used,  and  if  it  is  not  reclaimed  at  one  time  it  will  be  at  another 
if  returned  again  to  the  grease  trap. 

Class  Ull  —  Drain  Tile  Sewers.  The  tendency  of  drain  tile 
is  to  produce  a  uniform  moisture  condition  of  the  soil  by  draining 
water  from  wet  to  dry  soil.  To  prevent  damp  walls  the  following 
features  should  be  considered:  (i)  As  much  water  as  possible 
must  be  removed  from  the  soil  lying  against  wall.  (2)  The  wall 
must  be  made  impervious  to  water.  (3)  The  inside  face  of  the 
wall  should  be  sufficiently  well  ventilated  to  carry  off  the  moisture. 

The  first  requirement  is  the  only  one  that  can  be  improved  by 
use  of  drain  tile,  and  the  more  open  the  soil  the  more  essential 
becomes  the  use  of  tile.  With  regard  to  the  second  requirement, 
a  wall  may  be  watertight  through  certain  portions  and  yet  afford 
regular  channels  at  frequent  intervals.  Concrete  laid  at  different 
times  offers  fissures  through  which  water  can  flow.  Brick  work 
and  stone  work  have  enough  open  joints  to  keep  moist  the  entire 
surface  of  a  wall.  Plastering  the  outside  of  the  wall,  if  done  all 
at  one  time,  will  serve  best  to  make  the  wall  watertight.  If  drain 
tile  is  used  at  the  bottom  of  the  wall,  as  shown  in  Fig.  385  (Un-i), 
then  the  different  sections  of  ground  would  have  varied  amounts 


TILE  SEWERS. 


471 


of  moisture.  The  different  days'  work  of  concrete  are  shown  by 
the  lines  at  B.  If  a  course  must  be  stopped  before  finishing  it 
should  be  run  down  at  an  angle  as  shown  and  the  step  maintained 
as  though  it  were  longitudinal.  The  drain  will  prevent  water 
from  filling  the  soil  and  the  joints  are  "weathered"  so  that  water 
cannot  flow  through. 

The  drain  tile  at  the  bottom  of  the  wall  will  drain  only  the  ground 
above  it,  so  it  is  necessary  to  place  the  drain  well  below  the  floor 
line.  If  the  sewer  that  the  drain  tile  empties  into  lies  high,  necessi- 
tating placing  the  drain  at  A,  then  all  the  concrete  below  the  joint, 
B,  should  be  laid  at  one  time. 


Fio.  385  (Un-i). 


FIG.  386  (Ui2-i). 


Class  U12  —  Tile  Sewers  —  Sumps.  It  is  sometimes  impossible 
to  drain  parts  of  a  building  by  gravity,  and  to  remove  such  water 
a  sump  is  provided  with  some  form  of  pump  or  ejector.  In  locating 
a  sump  it  should  be  remembered  that  (i )  as  a  sump  must  be  placed 
lower  than  the  entire  drainage  system,  it  is  unavoidably  in  a  damp 
place;  (2)  through  oversight  or  accident  a  sump  may  overflow; 
(3)  being  located  in  a  remote  part  of  the  building,  it  will  receive 
but  little  attention.  These  conditions  make  the  use  of  belts  and 
electrical  machinery  very  unreliable  unless  placed  with  care.  A 
centrifugal  pump  is  well  suited  for  this  service  because  it  will 
handle  any  sand,  ashes  and  grit  that  may  be  carried  to  it  from 
the  drains. 

A  satisfactory  arrangement  for  this  service  is  that  shown  in 
Fig-  386  (Ui2-i).  The  pump  is  located  at  the  bottom  of  the 


4/2  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

sump  and  the  motor  where  it  can  have  good  care.  The  motor 
runs  only  when  there  is  work  to  be  done.  The  high  or  low  water 
alarm  will  relieve  the  necessity  of  watching  the  pump.  If  the 
operation  of  the  plant  is  dependent  upon  keeping  water  out  of  the 
sump,  then  a  steam  ejector  of  ample  size  to  take  care  of  extreme 
conditions  should  also  be  installed.  The  steam  line  to  the  ejector 
should  include  a  stop  valve  to  permit  of  shutting  off  steam  to  the 
sump  during  the  normal  working  of  the  plant. 


CHAPTER    XXXI. 
GAGE    PIPING. 

Class  VI  —  Sundry  Gage  Connections.  The  general  require- 
ments for  gages  on  steam  lines  are  described  in  connection  with 
Figs.  125  and  127.  A  gage  should  be  provided  for  each  section 
of  the  following  mains,  separated  by  a  valve:  Steam  header, 
feed,  auxiliary,  atmospheric  exhaust,  vacuum  exhaust,  dry  vacuum, 
circulating  water,  fire,  low  pressure,  oil,  compressed  air  and  city 
water.  Provision  should  also  be  made  for  installing  gages  for 
each  boiler,  and  if  an  automatic  feed  valve  is  used  one  should  be 
placed  between  the  pilot  and  the  feed  valve;  each  engine  to  show 
steam,  intermediate  and  vacuum  pressure;  each  feed  pump  between 
the  governor  and  the  steam  cylinder  and  between  the  stop  valve 
and  water  cylinder  at  discharge;  fire  pump,  to  show  steam  and 
water  pressure,  and  in  some  instances  to  show  vacuum  on  the 
suction;  condenser  circulating  pump  to  show  discharge  pressure 
(also  provide  attachment  for  vacuum  gage  on  suction);  dry 
vacuum  pump  between  stop  valve  and  pump  and  to  show  air 
suction;  automatic  pumps  to  show  condition  of  discharge  valve; 
oil  pumps  to  show  pressure  on  discharge;  engine  oil  piping;  each 
condenser  between  a  stop  valve  and  the  condensing  space;  econ- 
omizers, to  be  placed  near  blow-off  to  aid  in  handling  valve 
properly.  Gages  thus  installed  serve  two  purposes:  they  show 
whether  or  not  pressure  exists  and  also  indicate  the  amount  of 
that  pressure. 

In  addition  to  these  gages  it  would  be  well  to  install  a  pressure 
recording  gage  and  a  feed-water  temperature  recording  gage, 
a  permanent  draft  gage  showing  chimney  draft  and  another 
between  boiler  and  economizers.  If  a  specially  sensitive  draft 
gage  is  used  it  can  be  made  to  serve  two  or  more  points  by  having 
a  shut-off  valve  for  each  branch. 

A  simple  and  sensitive  draft  gage  is  shown  in  Fig.  387  (Vi-i). 
Water  is  placed  in  one  of  the  glass  cups  and  oil  in  the  other.  Instead 
qf  the  draft  being  measured  from  one  surface  to  another  in  these 

473 


474 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


glasses,  the  draft  is  measured  in  the  smaller  tubes.  A  column 
of  oil  10  in.  high  has  approximately  the  same  weight  as  9  in.  of 
water  and  for  every  tenth  of  an  inch  draft  the  gage  shows  one  inch. 
If  0.7  in.  draft  were  observed  on  the  gage  about  seven  inches  would 

be  indicated  on  the  scale  attached 
to  gage.  A  movement  of  10  in. 
in  the  small  glasses  with  J-in. 
bore  would  cause  a  movement 
in  the  large  glasses  (difference  in 
levels)  of  o.i  in.,  so  if  properly 
scaled  the  gage  may  show  i.i  in. 
draft  when  a  movement  of  10  in. 
has  occurred  in  the  o.5-in.  glasses. 
This  gage  can  be  readily  made 
by  any  engineer  having  a  lathe. 
The  pattern  work  is  extremely 
simple  and  rods  and  glasses  are 
standard. 

Class  V2  —  Sundry  Water  Col- 
umn Connections  and  Feed 
Regulators.  Water  columns  and 
connections  are  shown  in  Figs. 
115  to  124.  Boiler  feed  regu- 
lators are  shown  in  Figs.  194 
to  199.  These  illustrations 
show  the  steam,  water  and  feed 
valve  connections.  In  addition 
to  the  usual  water  column  con- 
nections there  should  be  a  blow- 
off  connection  from  the  bottom 
of  the  column  to  the  blow-off  line. 
In  many  plants  the  columns 
FIG.  387  (Vi-i).  are  blown  into  the  ash  pit :  a  satis- 

factory practice  unless  too  much 

water  is  blown  into  the  pit.  If  an  ash  hopper  is  provided  to  retain 
ashes  ready  for  discharging  into  an  ash  conveyor,  it  will  be  found 
best  to  keep  water  out  of  the  pit.  Water  in  the  pit  causes  the 
slide  grates  to  rust,  and  washes  in  grit,  making  them  troublesome 
to  operate.  If  an  open  funnel  is  used  to  receive  the  blow-off 
from  gage  cocks  it  should  be  drained  to  the  ash  pit.  As  but  little 


GAGE  PIPING.  475 

water  will  be  discharged  from  the  funnel,  and  as  it  will  always 
be  open  to  atmosphere,  the  blow-off  water  may  blow  back  through 
it.  This  will  necessitate  a  check  valve  at  the  bottom  of  funnel 
branch  to  make  it  a  safe  connection.  The  blow-off  lines  from 
the  bottoms  of  the  column  and  water  gage  should  run  separately 
down  to  a  point  within  reach  from  the  floor  and  a  valve  be  placed 
in  each  connection  before  it  connects  into  a  common  discharge. 

Steam  gages  are  sometimes  placed  at  the  top  of  a  column.  A 
gage  should  not  thus  be  subjected  to  the  sudden  pressure  changes 
and  the  liability  of  becoming  shut  with  scale  from  the  repeated 
blowing  of  the  water  column.  The  boiler  feed  regulator  should 
not  be  a  part  of  the  water  column,  but  independent,  having  separate 
steam  and  water  connections,  so  that  any  scaling  in  one  will  not 
affect  the  other.  When  so  connected,  if  a  water  column  does  not 
agree  with  the  working  of  the  feed  valve,  it  will  be  evident  that 
something  is  wrong;  but  if  both  connections  were  taken  off  of  the 
same  steam  and  water  connections  they  might  both  show  a  false 
water  level. 

Class  V3  —  Sundry  Connections  for  Damper  Regulators.  In 
general  the  hydraulic  damper  regulator  requires  a  pressure  line 
from  the  bottom  of  the  steam  header,  a  water  line  to  the  controlling 
valve  that  admits  water  to  the  plunger,  and  a  waste  water  line 
from  this  controlling  valve  to  relieve  pressure  on  the  ram.  There 
are  two  general  classes  of  regulators.  One  type  causes  the 
damper  to  be  opened  or  closed  completely  when  the  pressure 
for  which  it  is  set  is  reached  and  to  remain  so  until  the  other 
extreme  pressure  is  reached.  The  other  type  is  designed  to  open 
and  close  the  damper  gradually,  the  position  of  the  damper  at 
all  times  corresponding  with  the  various  pressures.  Regulators 
of  the  latter  class  do  not  maintain  the  steam  at  a  definite  pressure, 
but  control  the  fire  purely  from  a  commercial  standpoint.  They 
obtain  from  the  coal  the  greatest  possible  number  of  heat  units 
that  are  obtainable  by  damper  control.  Fig.  388  (V3~i)  shows  a 
regulator  of  this  type;  the  pressure  from  the  steam  line  is  con- 
nected to  the  under  side  of  the  diaphragm  and  the  pressure  on 
diaphragm  is  counterbalanced  by  a  weight  on  a  lever.  Some 
types  use  a  weight  to  load  the  lever,  others  use  springs;  that  shown 
is  provided  with  both.  Either  one  alone  will  not  give  the  desired 
adjustment  for  the  regulator. 

It  is  generally  found   most   economical    to   allow   about   five 


476 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


pounds  variation  in  pressure  from  the  time  the  damper  starts 
to  move  until  it  is  full  open  or  closed.  When  two  springs  are 
used  the  full  range  of  pressure  variation  .is  adjustable  as  follows: 
If  the  upper  spring  is  loaded  to  10  Ib.  in  tension  and  no  load  is  put 
on  the  bottom  spring,  then  the  balance  level  will  move  from  one 
stop  screw  to  the  other  with  a  very  slight  added  pressure.  If 


FIG.  388  (V3-i). 

top  spring  is  loaded  to  40  Ib.  and  lower  one  to  30  Ib.,  it  will  then 
require  a  very  considerable  pressure  variation  to  carry  the  lever 
from  one  stop  to  the  other. 

The  most  satisfactory  operation  is  obtained  by  setting  the 
spring  load  on  the  balance  lever  for  the  lowest  pressure  to  be 
carried,  say  100  Ib.,  and  either  slide  weight  out  or  hang  on  weights 
for  the  higher  pressures*  It  will  be  noted  that  the  diaphragm 
has  but  little  travel  and  that  it  is  supported  over  its  entire  surface. 
The  strain  caused  by  the  pressure  is  transmitted  to  the  segment 
jointed  blocks  shown. 


GAGE  PIPING.  477 

If  ample  provision  is  made  to  catch  the  drips  and  leaks  from 
the  regulator  it  should  be  placed  in  engine  room  in  charge  of  the 
engineers,  and  to  aid  the  firemen  in  handling  the  boilers  there 
should  be  some  form  of  telltale  carried  to  the  front  of  the  boilers 
where  the  firemen  can  observe  the  working  of  the  regulator. 
(See  Fig.  388.)  The  economy  effected  with  an  efficient  regulator 
is  sufficient  to  pay  for  one  of  the  most  approved  types  in  a  very 
short  time. 

Class  V4  —  Sundry  Relief  Valve  Connections.  There  are 
many  types  of  relief  valves,  as  previously  illustrated  and  described, 
as  follows:  '  Saftey  valves,  on  boilers,  Figs.  128,  129  and  130; 
cylinder  reliefs,  Fig.  159;  intermediate  receiver  reliefs,  Figs.  43 
and  134;  heater  reliefs,  Figs.  206  and  226;  pump  reliefs,  Fig.  216; 
and  special  types  of  relief  valves,  Figs.  182,  183  and  184.  Relief 
valves  are  also  required  on  economizers  and  air  compressors. 

The  boiler  safety  valves  are  constructed  so  that  a  less  pressure 
is  needed  to  hold  them  open  than  that  required  to  open  them,  but 
they  will  not  close  until  a  lower  pressure  is  reached.  There 
results  a  larger  discharge  opening,  a  quicker  discharge,  and  the 
valve  operated  a  much  less  number  of  times,  thus  greatly  reducing 
the  wear.  If  the  steam  pulsations  at  a  safety  valve  nozzle  are 
considerable,  say  three  pounds,  then  the  pop  relief  must  be  set 
higher,  say  five  pounds,  to  prevent  the  valve  from  chattering  on 
its  seat. 

Water  reliefs  are  generally  plain  spring-loaded  valves  that  open 
very  slightly  when  they  start  to  blow.  The  valves  shown  in 
Figs.  182  and  183  are  specially  suited  for  large  discharges  of  water, 
and  that  shown  in  Fig.  184  for  smaller  quantities. 

Class  V5  —  Sundry  Pressure  or  Speed  Regulator  Connections. 
A  satisfactory  method  of  piping  pump  governors  is  shown  in 
Fig.  89.  To  insure  smooth  running,  a  sufficient  volume  of  steam 
is  required  between  governor  and  machine.  (See  Fig.  93.)  An 
engine  driving  a  centrifugal  pump  or  running  at  different  constant 
speeds  should  have  a  slide  weight  governor  similar  to  that  shown 
in  Fig.  96.  Governors  that  control  pumps  delivering  against  a 
uniform  head  are  so  unchangeable  in  the  position  of  the  valve 
that  very  satisfactory  results  can  be  secured  by  hand  control. 
A  by-pass  should  be  placed  around  the  governor  on  such  a  pump, 
then  repairs  can  be  made  to  the  governor  while  the  pump  is  under 
hand  control. 


478  STEAM  POWER  PLANT  PIPING  SYSTEMS. 

It  is  advisable  to  furnish  feed  pump  governors  with  a  by-pass. 
Then  if  the  governor  is  controlling  the  pumps,  the  feed  valves 
may  be  opened  or  closed  to  regulate  the  feed  to  the  boilers.  If  a 
pump  is  hand  controlled,  regulation  requires  that  the  steam 
throttle  to  the  pump  be  changed.  This  increases  or  decreases 
the  delivery  of  the  pump.  Probably  the  best  control  is  obtained 
with  a  weight  so  hung  on  the  pump  governor  lever  that  it  may  be 
adjusted  by  a  screw  and  hand  wheel.  Then  for  regulation,  instead 
of  altering  the  feed  valves,  the  output  of  the  pump  can  be  altered. 

A  fire  pump  should  be  provided  with  a  by-pass  around  the 
governor  if  there  is  any  possibility  of  the  governor  being  dis- 
arranged while  in  operation.  In  case  of  fire  it  would  be  far 
better  to  have  a  man  stand  at  the  throttle,  working  it  by  hand, 
than  to  risk  a  poor  governor  interfering  with  the  water  supply. 
The  successful  continuous  operation  of  a  fire  pump  should  not  be 
dependent  upon  any  device  that  cannot  be  hand  operated  if 
necessary. 

For  every  given  speed  of  an  engine  driving  an  electric  generator 
the  governor  opens  the  valves  a  given  amount,  making  it  impossible 
to  secure  the  same  speed  with  different  amounts  of  valve  opening. 
If  a  condenser  is  thrown  on,  it  immediately  relieves  the  engine 
of  a  large  part  of  its  load,  and  to  reduce  the  steam  fed  to  the 
engine  it  is  necessary  for  the  engine  to  increase  its  speed  until 
the  port  openings  of  valves  correspond  with  the  smaller  amount 
of  steam  required.  Engine  governors  also  fail  to  "anticipate 
the  on-coming  variations." 

The  inertia  governor  has  been  in  use  for  a  considerable  time  on 
high-speed  shaft  governor  engines.  It  is  the  most  approved 
type  and  with  it  it  is  possible  to  secure  higher  speeds  with  a  heavy 
load  than  with  a  light  load.  This  is  because  the  valve  opening  is 
controlled  partly  by  the  retardation  of  shaft  rotation.  Such  retar- 
dation is  wholly  a  result  of  load,  not  speed.  There  are  a  few 
types  of  Corliss  inertia  governors,  but  as  they  are  operated  by  belts 
most  of  the  small  amount  of  acceleration  or  retardation  is  lost. 
High-speed  engines  have  their  inertia  governors  directly  attached 
to  the  moving  parts;  the  balance  wheel  is  relatively  light  and  sub- 
ject to  retardation  and  acceleration.  Heavy  Corliss  engines  are 
slow  in  this  inertia  movement  and  the  force  is  liable  to  be  lost  in 
the  governor  belt.  These  corrections  for  variable  loads,  and  for 
vacuum,  should  be  refinements  that  could  be  thrown  on  and  off 


CAGE  PIPING.  479 

at  will  and  not  make  the  regulation  of  the  engine  dependent  upon 
them. 

Class  V6  —  Sundry  Lubricator  Connections.  The  old-style  glass 
sight-tube  gravity  lubricator  should  not  be  ordered  with  new 
equipment  because  a  mechanically  driven  force  feed  pump  can 
be  secured  for  a  price  that  will  enable  it,  in  a  short  time,  to  effect 
sufficient  saving  in  oil  to  pay  for  itself.  The  larger  engine  builders 
furnish  good  types  of  force  feed  pumps  and  all  necessary  connec- 
tions. An  oil  pump  invariably  delivers  far  more  oil  than  is 
required,  and  if  two  feeds  are  used  they  should  both  lead  to  the 
steam  line.  It  would  otherwise  be  quite  difficult  to  cut  down 
the  stroke  or  oil  discharge  sufficiently  if  two  were  working.  The 
same  principle  should  be  observed  for  small  stoker  and  fan 
engines  which  get  too  much  oil.  Rather  than  use  a  two-plunger 
pump  it  will  be  better  to  use  in  conjunction  with  a  small  single- 
plunger  pump  a  plain  gravity  cup  available  for  emergency  cases. 
If  a  pump  is  compound  then  a  larger  oil  pump  can  be  used  with 
it,  having  a  dividing  partition  so  that  two  kinds  of  oil  may  be 
fed.  In  practice,  however,  it  has  been  found  that  little  or  no 
additional  oil  is  required  for  low-pressure  cylinder  other  than 
that  which  is  carried  through  from  the  high-pressure  end.  By 
using  a  two-compartment  pump,  each  compartment  having  one 
plunger,  both  feeds  may  serve  the  high-pressure  cylinder,  or  if 
one  pump  will  serve  the  other  may  be  held  in  reserve  or  be  used 
with  low-pressure  oil  for  low-pressure  cylinder.  _. 

Class  V7  —  Sundry  Trap  Connections.  St^am  traps  are  com- 
monly looked  upon  as  a  nuisance,  but  there  are  situations  which 
will  permit  of  no  other  method  of  doing  their  work.  If  a  plant 
is  carefully  laid  out  it  is  quite  probable  that  traps  will  not  be 
required  for  any  of  the  steam  lines.  Steam  machines  will  take 
through  them  considerable  condensation  and  oftentimes  a  trap 
need  not  be  used;  but  in  this  connection  it  must  be  remembered 
that  for  every  pound  of  condensation  sent  through  a  steam 
machine  there  is  a  loss  of  one  pound  of  steam  in  addition  to  the 
loss  of  condensation  by  using  steam  in  this  condition.  If  there 
is  no  other  way  of  freeing  a  steam  line  of  this  entrainment,  then 
a  trap  should  be  used,  even  if  it  is  necessary  to  blow  the  drips  to 
waste. 

The  intermediate  receiver  has  virtually  no  other  way  of  dis- 
charging its  drips  except  through  a  trap,  and  to  unify  the  respon- 


480 


STEAM  POWER  PLANT  PIPING  SYSTEMS. 


FIG.  389  (V7-i). 


sibility  for  a  satisfactory  engine  installation  it  will  be  found 
advisable  in  ordering  an  engine  to  specify  that  the  builder  furnish 
the  trap.  A  trap  for  receiver  service  should  be  of  large  capacity. 
The  use  of  two  valves  seated  simultaneously  is  questioned,  because 
this  is  a  form  of  construction  that  it  is  next  to  impossible  to  keep 
tight.  The  trap  shown  in  Fig.  330  is  suitable  for  receiver  service. 
Either  of  the  two  valves  can  be  seated  separately.  To  permit 

repairs  it  is  necessary  to  have  a 
by-pass  with  a  valve  and  also 
valves  in  the  trap  inlet  and  outlet. 
In  ordering  a  by-pass  it  is  gener- 
ally understood  that  these  three 
valves  are  required  whether  the 
by-pass  be  for  a  trap,  governor, 
reducing  valve  or  any  other  flow- 
regulating  device. 

In  addition  to  the  by-pass  all 
traps  should  have  a  blow-off  con- 
nected to  the  trap  discharge  line.  Fig.  389  (Vy-i)  shows  a  trap 
with  a  drip  inlet,  A,  a  drip  discharge,  B,  a  trap  blow-off,  C,  and  a 
by-pass  valve,  D.  It  will  be  noted  that  the  three  unions  are 
located  between  the  valves  and  the  trap,  permitting  the  trap  to  be 
removed  at  any  time,  even  though  there  is  pressure  on  the  drip 
line.  It  will  also  be  noted  that  all  the  connections  drain  into  the 
waste  and  thus  are  safe  against  freezing  if  out  of  service. 

Class  V8  —  Sundry  Plugged  Openings  and  Air  Vents.  The 
bottoms  of  water  pump  cylinders  are  invariably  supplied  with 
plugs,  but  these  are  generally  made  of  cast  iron.  Brass  should 
be  used  instead  of  iron  because  iron  plugs  are  liable  to  rust  in  so 
they  cannot  be  removed.  If  a  plant  is  to  be  shut  down  and  there 
is  a  possibility  of  water  freezing  it  is  absolutely  necessary  to  drain 
the  water  out  of  all  pipes  and  machines  to  prevent  them  from 
being  damaged.  All  exhaust  and  steam  branches  not  having 
permanent  drains  should  be  provided  with  plugged  openings  at 
each  low  point.  A  plugged  opening  should  be  provided  in  the 
feed  main  next  to  a  pump  and  another  at  the  extreme  end  of  the 
feed  line  so  that  a  gage  may  be  used  if  desired.  Tapped  openings 
should  also  be  provided  in  a  compressed  air  line,  one  close  to  the 
compressor  and  another  at  the  extreme  end  of  the  line.  The 
vacuum  lines  should  also  have  plugged  openings  at  the  condenser 


GAGE  PIPING.  481 

and  at  the  engine.  These  different  plugged  openings  should  be 
provided  before  the  pipe  lines  are  blown  out,  as  considerable 
risk  is  run  in  drilling  and  tapping  into  lines  that  are  liable  to  carry 
chips  into  cylinders  or  valves. 

The  gage  openings  should  be  0.25  in.  and  closed  with  brass 
plugs.  Openings  for  thermometers  may  be  plugged  also  if  there 
is  no  certainty  of  their  immediate  use.  The  openings  in  smcke 
flues,  furnaces,  etc.,  to  obtain  temperatures  and  draft  readings 
should  all  be  determined  early  in  the  work  and  their  locations 
stated  so  that  contractors  may  not  overlook  them.  A  pipe  sleeve 
should  be  built  in  such  walls.  The  outside  of  the  walls  will 
generally  be  found  cool  enough  so  that  a  wooden  plug  will  stand 
the  heat ;  if  not,  a  washer  with  a  small  hole  in  it  can  be  placed  over 
a  yVin.  spring  cotter,  the  ends  of  the  cotter  being  allowed  to  spring 
open  and  hold  washer  up  against  the  end  of  the  pipe  sleeve. 

To  avoid  rumbling  in  closed  heaters  and  economizers  it  is  neces- 
sary to  discharge  the  air.  A  small  blow-off  should  be  provided 
for  this  purpose.  This  blow-off  may  be  open  to  the  atmosphere  if 
desired,  because  it  will  be  closed  as  soon  as  it  has  served  its  purpose 
in  discharging  the  air.  A  valve  J  in.  or  f  in.  in  size  would  be  of 
ample  size  as  an  air  blow-off  for  almost  any  heater  or  economizer. 
It  is  the  usual  practice  to  use  the  blow-off  at  the  extreme  top  of  a 
heater  for  a  scum  blower  as  well  as  to  discharge  air.  At  the  top 
of  an  economizer  there  would  be  placed  only  the  relief  valve,  but 
an  air  vent  also  should  be  placed  at  the  top  of  the  upper  economizer 
manifold.  A  careful  operator  desires  neither  water  hammering 
nor  snapping  in  pipe  lines  and  station  apparatus.  If  he  is  in 
doubt  as  to  the  amount  of  pressure  at  the  end  of  a  line  there  should 
be  means  for  his  determining  it. 

There  is  too  strong  an  inclination  on  the  part  of  the  employer, 
and  to  a  large  extent  on  the  part  of  the  designing  engineer  also, 
to  limit  power  station  facilities  to  those  readily  apparent  as  abso- 
lute essentials.  Rather  than  reduce  these  facilities  to  the  least 
possible  amount  it  would  be  better  to  slightly  overdo  and  afford 
the  operator  every  means  for  doing  his  duty  well,  even  though  a 
few  of  these  means  provided  are  never  used. 


INDEX 


Air  cleaning,  hose  connections.  . .     408 
compressor,  cooling-water  tank .      407 

for  fire  protection 410 

lift  for  artesian  well 366 

pressure     tanks,      multi-ported 

change-over  valves 409 

whistles 4IQ 

Artesian  pump,  control  when  far 

from  plant.  .    357,  358,  362,  364 

water,  air  lift 366 

condensing  plant 44,  45,  364 

for  fire  protection 363 

pumping  cost 355 

storage 357,  358,  362,  364 

well,  at  elevator  shaft 368 

construction 359,  360 

drive  head 361 

why  not  in  power  plant 358 

Ashes,  objections  to  wetting.  . .  .      474 
Atmospheric  relief  valve,  essential 

features 180 

for  vacuum  reliefs,  177,  178,  179 

regrinding 178 

Auxiliaries,    condensing    or    non- 
condensing 75,  187,  263 

motor  driven,  where  economical     344 

Back  pressure  valves . 199 

Bids,  form 6 

specifications 90 

Blow-off,  amount  of  vapor  formed 

in  blowing 456 

cistern  away  from  building.  . .  .  457 

cistern  or  tank 70,  71 

cistern  without  vent  pipe 457 

basin    in    condenser    discharge 

waterway 449 

down-flow    created     in     sewer 

manholes 456 

elastic  connections.  ...  451,  452,  453 

flow  denoted  by  sound 455 

for  automatic  drip  pump 421 

for  steam  header 142 

freedom  to  expand  when  under- 
ground   457 

main  higher  than  boiler  open- 
ing   453 

not  used  as  boiler  washout,  69,  451, 

452,  453 


Blow-off  (continued). 

pits  back  of  boilers.. .450,  451,  452,  453 
removable  from  its  underground 

conduit 457 

requirements 67,  449,  450,  454 

steam  in  sewers 456 

trench  and  cover  plate,  450,  452,  453 

vacuum  prevented 68 

valves  in  pairs.  ...   69,  451,  452,  453 

vapor 70 

standpipe 456 

Board  of   underwriters,    see   Fire 

Protection. 

Boiler  cleaning,  not  through  blow- 
off 69,  451,  452,  453,  467 

number  of  units 25 

scale  box 469 

compound,  chemical 393 

feed,  automatic  control,  224,  225,  226, 

412 

boiler  inlet  tube 222 

chattering  of  valve 223 

city  water 349 

combined  feed  and  check.  .  .      222 

conditions  necessary 37 

double  connection 221,  239 

excessive  pressures 214,  229 

for  no  other  purpose 30 

make   up    water,     see    Con- 
densers. 

materials  to  use 217,  219 

suction  jet  condenser 312 

surface  condenser,  48,  261,  262,  265 

thermometer  pots 228 

uniform     distribution     and 

pressure 219,  220 

valve  extension 223 

water  see  Water. 

cleaning,    see    Filter    and 
Grease  Extractor. 

priming 411 

room  floor  drains 450,  466,  468 

scale,  laminations 392 

Boiler-shop  work,  expansion  joints,  172, 

173 
large  pipe  and  fittings,  172,  173,  195 

water,  purification 395 

Building,    concrete    walls,  water- 
proof       471 


483 


4^4 


INDEX. 


Building  (continued). 

details  to  provide..  .  273,  321,  324,  368 

to  secure  dry  walls 471 

By-pass,  part  of  valve.  ...  126,  127,  128 

'of  piping 124 

Catch  basin;  for  engine  room  floor.     466 
to  keep  cinders  out  of  sewer,  466,  468 

Chemical  pump 107, 108 

Chemical  treatment  of  water,  see 

Water. 
Cinder  catch  basin  to  keep  cinders 

out  of  sewer 466,  468 

City  water,  for  emergency  use,  348,  351 

for  fire  service 385 

meter  location 347 

obtained  without  metering.  .  .  .      345 
supply  from  two  distant  points.     350 

waste  of 342,  348 

Classification,  see  Table  of  Contents 

and  subclasses no 

Cleaning  boilers;  wash  water  kept 

out  of  blow-off,  451,  452,  453 

electrical  apparatus 79,  408 

floors;  with  hose 281 

oil  tanks 141,  282 

water  tube  boilers 240,  241 

Coal  and  ash  system 403 

Condensation  losses 411 

also  see  Steam  Drips. 
Condensers: 

also  see  Cooling  Towers,  Pumps 
and  Water  Ways. 

circulating  water 42 

circulating  water  raised  to  enter 

heater 263 

counter  current 51,  52 

discharge,  elevation 308 

elevated  jet.  .    44,  305,  306,  315,  316 

advantages .'     311 

air  cooler 50 

air  discharge !  ...  50,  51 

inclined  tail  pipe 315 

special  air  ejecting  tail  pipe.  .     330 

false  injection 310 

for  atmospheric  exhaust 343 

house  away  from  power  plant.     306 
illustration    of    air    and    water 
movement  in  wet  vacuum 

PumP 33i 

injection,  controlled  by  thermo- 
stat   3IQ 

separate  for  feed  water 185 

suction  jet,  boiler  feed 312 

efficiency 3og 

surf.ace 45,261,265 

air  discharge 51,  52 

makeup  water 261,  265,  269 

vacuum  affected  by  air 328 


Condensing  plant,  on  high  ground, 

jet  type.  ..  .  305,306,315,316 
on  high  ground,  surface  type,     308 

operation  economics 289 

without  heater 27 

Conductors,  injured  by  vapors..  .      159 

location 1 58 

Connections,  long 121,  122 

strained 115,  116,  118 

Contractors,  and  detailers 5 

bids 6,  20 

what  they  should  do 4 

Cooling   pond,    construction 291 

grease  separator 314 

requirements  for  same 291 

surface  required 305 

Cooling  tower,  artesian  water.  .     44,  45 
case  of  no  saving  in  operating 

cost 325 

construction 322 

cost    and    efficiency,    304,    322,    327 
efficiency  effected  by  design.  .  .      324 

surface  required 305 

Cooling    water,    with    circulating 

tank 283,  284,  407 

Corrugated  joints,  for  expansion.      174 

Cost,  initial;  of  pipe  work 2 

savings 5,6 

system,  extra  valves 43 

Cylinder  lubrication,  see  Lubrica- 
tion. 

Damper    regulator,     construction 

and  operation 476 

diaphragms 142 

operated     with     low     pressure 

water 353 

Designers  (see  Engineers^). 

Detailing,  pipe  work 5,  6,  109 

Diagrams,  completeness 20 

determination  of  equipment.  .    7,  109 

development 36 

elevations 15 

furnished  by  contractor 20 

making 7,  109 

operation  guide 7 

studies 15,  109 

Diaphragm     joints,     for     expan- 
sion  ^  172,  173,  174 

Division  of  plant  into  sections.  ...  24 
Draft  gage,   construction  of  sen- 
sitive type 474 

Drain,  air  lines 79 

also  see  Steam  Drips. 
Drainage  pump:  to  raise  sewer- 
age  '...  471 

Drawings,  also  see  Engineers,  Con- 
tractors and  Detailing, 

starting  work 109 


INDEX. 


485 


Drinking  water,  artesian  well.  .  .  .      365 

requirements 354 

Dripping  pipes,  sweating 348 

Drips,    see     Drains,    and     Steam 
Drips. 

Earth    work,    filling    trenches,    to 

prevent    293 

for  cooling  pond,  dam  and  spill- 
way        291 

scraping  off  surface  of  ground 

for  deep  water  way 317 

Economizer,  accessibility 229,  230 

blow-offs 69,  454 

cleaning,  results 35 

efficiency 29 

flow  in 229,  230 

heater  also  used 75 

installation  advisable 45 

pressure  lower  than  boiler  pres- 
sure      18,  256,  285 

separate  groups 29 

Elevator,  hydraulic,  brass  shell  for 

ram 403 

for  coal  or  ash  system 402 

construction  details 405 

control  valve 406 

for  high  lift 406 

Engines     arranged     for     oiling 

system 89 

Engine,  automatic  stop  valve.  . .  .      176 
connections,     intermediate     re- 
ceiver        64,  418 

live    steam    to    low    pressure 

cylinder 159 

reheater 165,  418 

table  of  sizes 181 

too  rigid  for  expansion 161 

to  run  either  high  or  low  pres- 
sure alone 160,  186 

damaged  by  water 419 

device  to  catch  drips  of  piston 

rod 460 

drips  and  drains,  collected 418 

see  also  Drips, 
governing,  speed  changes  under 

different  pressures 478 

intermediate  receiver  and  sepa- 
rator     117,  418 

journals,  water  cooled 278 

lubrication 435 

port  openings 182 

starting 162,  418 

vacuum  breaker 176 

valves,  reducing,  see  Valves, 
warming  connection,  advantages,     418 

wattmeter 176 

Engineers,      designing;      careless 

engineering 1,3 


Engineers  (continued). 

designing;  what  they  should  do.         4 

operating;  ability 2 

operating;  when  not  at  fault.  . .          2 

Entrainer,  for  exhaust  lines 201 

for  large  vacuum  lines 182 

for  small  lines 203 

vacuum     exhaust     trap        (see 
Vacuum). 

Equipment,  provision  for  future. .  24,  25 

right  or  left  hand 36 

to  suit  piping 15 

to  suit  system 22 

when  and  how  to  order 9 

Exhaust  drips,  ball  trap 422 

from  exhaust  head 197,  418 

to  heater 199,  200 

U  trap 196,  418 

fittings,  see  Fittings. 

for  under  grates 204 

light  construction 193 

roof  sleeve 197 

undesirable  features 73 

velocity  of  flow 198 

Expansion,  corrugated  joints.  ...      174 

diaphragms 171 

elasticity  of  fittings 115 

elasticity  of  pipe 112,  114 

rigid  piping 13 

slip  joints 318 

U  bends 113 

Extras,  avoidance  of 20,  no 

Feed  main,  see  Boiler  Feed. 
Filters,  cleaning,  see  Cleaning, 
grease  extractor,  see  Grease, 
oiling,  see  Oiling. 

sand,  etc.,  in  water 254 

water  after  entering  boiler,  395,  396 
also  see  Water,  chemical  treat- 
ment. 
Fire   protection,    air   injection  of 

extinguishing  powder,  79,  387, 
388,  410 
artesian  water,  automatic  water 

valve 374,375 

care  of  oils,  grease,  etc 387 

city  water < 385 

electric  alarm  svstem 377 

fire  pump,  see  Pumps. 

general   requirements,   376,  378,  381 

hose 377 

hose  cart 380 

hose  racks  and  reels,  381,  382,  383, 

384 

hydrants 41.  379 

indicator  posts 41)  380 

inside  lines 373>  380 

insurance  requirements.  .  '.  .  .  42,  372 


486 


INDEX. 


Fire  mains  used  for  other  service.     386 

meter  arrangement 345 

pipe  lines  protected 371 

roof  sprayer  and  stand  pipe.    370,  384 
separate  room  for  pump.  .  372 

water  main 40,  4J>  37^ 

water  storage,  see  Water. 
Fire  tile,  in  place  of  water  cooled 

devices 285 

Fittings,  flanged 202 

flanges  on  pipe 194 

of  plate iQ5 

welded  plate 114 

Force  draft  flues 26,  28,  29 

Floor  drains 72 

floors  pitch 464 

guarding  against  back  water. .  .     462 
Frictional  resistance  of  piping.  .  168,  326 
Future  equipment    blind   flanges,       74 
Future  requirements,  see  Equip- 
ment. 


Gage-boards 152, 153 

Gage  cock,  forced  tight 148 

deceptive  pressure  reading..  .151,320 

illumination 152,  153 

shut-off  needle  valve 151 

single  and  double  tube 151 

suction  line 256 

where  generally  required 473 

Galvanized  pipe,  where  required.     348 

Gaskets,  for  vacuum  lines 175 

Governor,  air  compressor 130 

draft  fan  engine 1 28 

engine 126,  187 

feed  pump 127 

fire  pump 127,375 

float  type 135*265 

for  engines 478 

for  a  set  of  steam  machines.  .  .      133 

for  oil  pump 85,  437, 438 

range  of  pressures  adjustable.  .     132 
rotative  dry  vacuum  pump.  . .  .      130 

stuffing  boxes 129 

vacuum  pump 129 

Grease    extractor,   exhaust    sepa- 
rator   184,  282 

for  boiler  feed  water 253 

separator,  cooling  pond 314,  315 

sewer,  discharge  of   vapors...     458 

for  oily  drains 71,  458 

grease  catcher  tank 458 

means  of  saving  grease 461 

to  catch  cylinder  oil  drips  off 

piston  rods 459 

to  receive  pump  pan  drips.  .     460 
underground  line  free  to  ex- 

458 


Heaters,  air  discharge 53,  54 

direct  and  counter  current 53,  54 

lavatory  see  Lavatory. 

live  steam 158 

live  steam,  see  Purifier. 

number  to  install 32 

omitted  in  condensing  plant.  .  .        29 

open 44,  45,  48,  49,  251,  277 

loss  feeding  water  under  pres- 
sure       277 

or  closed 33,  268 

surface  condenser 48 

steam  tube  and  water  tube  type     231 

vacuum  type .  . 45 

water  supply 33,  277 

Heating  system,  automatic,  back 

pressure  valve 213 

back  pressure  control 137 

drip  return 49 

exhaust,  non-condensing 

plant 212 

exhaust     steam,     condensing 

plant 210 

exhaust,  upflow  of  drips.  ...      211 
live  steam  coil  and  control.  .      141 

using  economizer  water 285 

vacuum  return 209 

High  water,  in  boilers 412 

Hose,  for  fire  service 377 

for  washing  floors 281 

for  wetting  down  ashes 281 

used  for  emergencies 266 

Hot  water,  circulating  system.  ...      287 

Hot  well,  air  discharge 252,  334 

construction 251,  252,  306,  313, 

3i5»3i6 

fumes  from  foul  water 334 

grease  discharge 251,  252,  253 

Hydrants,  see  Fire  Protection. 
Hydraulic  Elevator,  see  Elevator. 


Ice,  mouth  of  water  way  intake,  299,  313 

Inconsistencies,  in  systems 14 

Injury,  atmospheric  valve  opening       73 

by  open  blow-off 69,  452,  455 

Insurance,  see  Fire  Protection. 
Intake,  see  Water  ways. 

Lavatory,  arrangement  of  fixtures,  464 

hot  water 157,  158,  237,  287 

low  pressure  water 286 

soil  pipe 462 

provided    with    flushing   ar- 
rangements    464 

wash  stands  to  use 348 

Lawn  sprinklers,  hose  connections  42 

Lift,  see  Elevator. 

Live  steam  purifier,  see  Purifier. 


INDEX. 


487 


Low  pressure  service,  safe  against 

higher  pressures 271 

Low  pressure  service,  uses  for.  .    30,  271 

Lubrication,  atomizer  feed 434 

cylinder  oil  tanks 445,  447 

destructive     effect    of    sudden 

starting  of  engine 418 

different  oils  for  different  appli- 
cations       434 

different  oils  for  different  pres- 
sures     80,  82,  86 

feeding  devices 83,  85,  434 

forced  feed 86,  433,  434,  479 

journal  lubrication,  see  Oiling. 

low  pressure  cylinder  oil ....     82,  83 

means    for    keeping    record    of 

consumption,  86,  435,  445,  446 
method  of  feeding  oil  into  steam,  433, 

435 

piped  system,  doubtful  economy,  83, 
84,  86,  433 
steam     pump     with     pressure 

governor 84 

using   condensation  water  col- 
umn     81,  82,  479 

Mains,  as  equalizer 114 

in  place  of  direct  connection ...  47 

steam  drip  separator 116 

Make  up  water,  see  Condensers. 

Meter,  for  city  water .345,  347 

electrical,  at  engine 176 

for  each  shop  or  building 354 

friction  offered 234 

inaccuracies 41 

oil 87,  91 

portable 235 

water,  for  entire  plant 34 

location 33 

separate  for  each  boiler 38 

Moisture  passing  through  walls.  .  471 

Oil  barrel,  elevator 445 

emptying  sink 445 

emptying  valve 447 

storage 445 

characteristics 88 

cylinder  oil  devices,  see  Lubrica- 
tion. 

drip  lines 102,  143 

drip  main  folds 98,  432 

drip  pots  at  engines 433 

essential  requirements 430 

impurities,  to  be  removed 439 

in  feed  water 44 

lines   at   engines,    essential    re- 
quirements    431 

at  engines,  pipe  supports...  .  432 

flush  bore  unions 430 


Oil  lines  (continued). 

smooth  bore 429 

tight  joints . . 429 

pump,  accumulator  type  gover- 
nor      437 

motor  drive 437 

power  drive 437 

submerged  type 437,  438,  443 

storage,  requirements...  .  80,  387,  445 

tanks : 445,447 

tank,  cleaning 101 

Oiling,  air  pressure  tanks,  multi- 
ported  change  over  valves     409 
automatic  separation  of  oil  and 

water 99,  440,  443 

device   to   prevent   cylinder  oil 

getting  into  system 460 

engines   not   arranged  for  sys- 
tems        89 

feeding  devices.  ...    91,  92,  435,  436 

filters 97,  143,  443,  444 

grease,  where  preferable 90 

hand  feed,  where  preferable.  .  .       89 
oil  and  water  incorporated.  . .  .95,  443 

points  to  draw  oil 447 

precipitation  of  impurities,   98,  440, 
441,  442,  443 

sewers  for  washouts 470 

stream  feeding 89 

system,    a   convenience,    not    a 

necessity 91 

air  pressure 94 

requirements 93 

two  batch 98,  443 

water  pressure 95,  353 

Open  drains,  open  and  covered,  450,  466 
Open    sewer,    with    and    without 

cover  grating 466 

Operation,  continuous 14 

economics 14,  289 

simplified 104 

unsatisfactory,    caused    by    im- 
proper design i 

Outside  work,  see  Separate  build- 
ings. 

Packing,  see  Gaskets. 
Plumbing,  see  Lavatory. 
Power  plant  site,  elevations  to  con- 
sider        290 

suitable  for  cooling  pond,  291,  355 

water  supply  to  investigate,  290,  355 

Precipitation  tank,  for  feed  water,  395, 

396 

Priming  of  boilers 411 

Pump,  air  bound 248,  260 

artesian,  se?  Artesian  water, 
artesian  well,  356,  360,  361,  367,  368 
automatic  drip  return.  ...  56,  58,  421 


488 


INDEX. 


Pump  (continued). 

centrifugal,  removal  of  air 247 

chemical,  purification..  .  107 

controlled   by    condensation   in 

surface  condenser.  . .  .  261,  265 

controlled  by  float 274 

controlled    by    water    in    open 

heater 265 

cylinder  cooling 51,  279 

cylinder  drains 41? 

drip  pans  for  top  of  foundation     460 
dry  vacuum,  27,  50,  260,  328,  333,  336 

ele'ctric 3° 

feed  and  fire,  arranged  for  dif- 
ferent services 371 

fire  compound 32 

considerations     in     purchas- 
ing  239,375 

used  on  low  pressure  service,  30, 
374,  375,  386 

foot  valves 247,  248 

for  circulating  water  after  reach- 
ing boiler 396 

for  high  temperature  and  pres- 
sure      339 

governors,  see  Governors. 

heater  supply,  34,  260,  262,  268,  269 

located  center  of  plant 37 

mechanically  operated  valves.  .     337 

number  required 30 

oil 84,  85,  99,  102,  437,  438 

pans,  with  partition  to  separate 

water  and  steam  drips  .  .     469 

plungers  for  hot  water 251 

priming  connections 247,  280 

relief  valve 58,  215,  216,  229 

service  requirements 31 

sewerage 471 

suction  lines,  see  Suction. 

speed  indicator 340 

steam  condensation 339 

Y  steam  connection 125 

wet    vacuum,    without    suction 

valves 337 

Purifier,  live  steam,  163,  233,  393,  394 
skimmer  in  boiler 394 

Records,  oil  used 87 

Reducing  valves,  see  Governors. 

Repairs,  arrangements  for 12 

no  opportunity  for 2,  14 

operation  uninterfered  with.  ...        76 
Responsibility,  design  and  construc- 
tion        6,  21 

making  bids 20,  21 

Riveted  work,  difficulties in 

Roof  conductors,  protected  against 

frost • '  462 


Roof  sleeves,  for  exhaust  pipe 
for  safety  valve  pipe 


197 
155 


Safety    valves,    disturbance    from 

blowing  off ..  .  . 154 

drain 155 

pulsation  with  engine 156 

roof  collars 155 

where  to  connect  to  boiler 157 

Sagging    pipes,    imperfect    drain- 
age    203 

Sample  plant 24 

Savings,  see  Operation,  and  Cost. 
Scale   retaining   box,   for   holding 
boiler  scale  while  clean- 
ing    469 

Screen  house,  see  Water  ways. 
Separate  buildings,  hot  water  sup- 
ply   287 

low  pressure  water  supply.  .287,  354 

steam  drip  return 423 

Separator,  exhaust 184 

steam 413,  414 

Settling    tank,    see    Precipitation 

tank,    Water,    Chemical 

Treatment    and    Oiling. 

Sewers  back-water  check,  placed 

in  inspection  pit 465 

blow-offs,  see  Blow-off, 

from  boiler  washouts,  451,  452,  453, 

467 

material  to  use 462 

pitch  of 467 

protected  from  frost 463 

Sewerage  pump,  for  low  drainage,  471 

Shop  standards,  heavy  work in 

Side  opening  catch  basin,  avoid- 
ing holes  in  floor 464 

Sight,  to  show  amount  of  flow  in  a 

pipe 353 

Signal  whistles,  air 410 

Skimmer,  for  boilers 394,  395 

Smoke  flues 26,  28,  29 

Soil  pipes;  connected  sewers  that 

flush  same 462 

distinct  but  in  same  trench  as 

condenser  discharge ....  464 

Soot  blower  cord  valve 136 

horizontal  or  vertical  passes.  .  .  137 

Specification,  engine  port  openings,  182 

guide no 

Specialists,  pipe  work 5 

Specials,  fittings 112 

Steam    drips,    atomizer    for    ele- 
vating drips 426 

discharged  into  auxiliary  steam 

main.  . 61,  64 


INDEX. 


489 


Steam  drips  (continued). 

economy  of  returning  to  boiler     428. 
engine   and   boiler   branches,    115, 
118,  119,  121,  122,  413 
exhaust  drips,  see  Exhaust. 

from  boiler  valves 122 

from  reheater 55,  63,  418 

from  outside  buildings.  . .  .424,  427 
general     features     governing 

handling  of  same 424,  428 

gravity  return  to  boilers,  55,  61,  64, 
414,  426 

main  header 114,  115,  415 

of  different  pressures,  55,  56,  59,  64, 

415 

priming  of  boilers 411 

return  against  steam  flow.  .  .      120 

returned  by  impact 58 

return  to  boiler  direct,   55,  57,  415, 

428 

steam  loop ; .  .     419 

steam  separator 117,  123,  413 

sound  alarm  when  not  working,  55, 

61,  64 

tank  to  collect  all  engine  drips     418 

through  trap  to  heater 57 

up  flow 426 

water  hammer,  see  Water, 
with  automatic  receiver  pump       56 
separators,  different  forms..  .413,  414 
traps,  economy  in  their  use  ....      479 

pilot  control 423 

Storage  tanks,  see  Water,  Oil,  Air, 
Grease  and  Blow-off 
Tanks. 

Structural  work,  tank  supports.  .      277 
Suction  line,  affected  by  organic 

matter  in  water 259 

air  chambers 249,  250 

air  in  pumps 243,  244,  247 

air  in  pump  suction 244,  259 

concrete  protection 246 

gages 256 

hot  water 251,  259,  262,  265 

.  labor  difficulties 245 

pumps  air-bound 244 

pump  clearance 243 

pump  lift 243,  259 

suction  well 245 

tile  water  ways 246 

underground  work 245,  293 

water  hammer 250 

Superheated  steam,   condensation 

in  pipe 167,413 

high  velocity 168,  412 

requirements 412 

variable  temperature  in  pipe...     166 
Sweating  of  pipe  lines 348 


PAGE 

System,    made    when    there    was 

none 21,  77 

maintained  by  rearrangement,  77,  112 
Systems,    determining   most    suit- 
able    12,  23,  109 

System,  possible  but  not  desirable       15 
secondary  or  minor 14 

Tanks,  see  Water,  Oil,  Grease  and 
•  Blow-off  Tanks. 

Thermometer,  connections 228 

Tile  pipe,  leaky  joints :  293,  294 

Traps,  steam 423 

Trenches,  see  Underground  piping. 
Tube  cleaner,  hydraulic.  .  .  30,  240,  241 

Turbine,   pressure  vibration 169 

superheated   steam,   see  Super- 
heated. 

U  bends,  see  Expansion. 
Underfeed  stoker,  pipe  lines  and 

control 205,  206 

Underground  piping,  buried,  135,  292, 

293 

conduit 164 

protected  against  frost 463 

trench 135,  207,  427,  450 

Units,  same  size,  advantages.  ...        23 
size  of 23 

Vacuum  breaker,  hand  control.  .  .      176 

exhaust  trap,  construction 423 

leaks,  through  metallic  packing     332 

lines,  testing  for  leaks 332 

losses,  engine  and  turbine 170 

separator,  grease  extractor •  184 

Valve,    automatic    back    pressure, 

heating  system 213 

automatic  engine  stop 176 

back  pressure 199 

cylinder  relief 191 

float  type,  for  tanks 276 

for  hydraulic  elevator  control.  .      406 

large,  for  water  way 301 

location 47 

motor  operated 160,  176 

objectionable  if  light 115,  175 

reducing,  for  engines 187 

regrinding  seat 178 

,  relief,  pilot  control  and  direct,  215,  216 
suction  or  foot 248 

Vapors,  see  Blow-off. 

Vibration,  faulty  design 121,  123 

Water,  chief  station  requirement,   290, 

355 

chemical  treatment.  .      104,  106,  389 
condensing  plant 44 


490 


INDEX. 


PAGE 

Water,  chemical  treatment  (continued). 

continuous  open  system 107 

continuous  pressure  system..     108 

cost 400 

demonstration 401 

intermittent  open  system,  105,  390, 

399 

column,  blow-off 69 

bracket  support 144 

electric  alarm .' .  .     149 

low  down  type 146 

operating  chains,  etc.,  omitted    148 

shut-off  valves 145 

whistle  alarm 150 

compound  fed  to  boilers 393 

dam,  to  prevent  erosion 291 

to  remain  water  tight 292 

niters 108,  253,  254 

gage,  illumination 147 

self  closing 147, 148 

heater,  see  Lavatory  and  Heater, 
precipitation      after      reaching 

boiler 396 

Water  pump,  control 274 

structural  support 277 

purification,  after  entering  boiler,   395, 

'396 

reliefs,  for  pump  discharges,    215,  216 

storage,  high  and  low  elevations     267 

pond  or  basin,  257,  357,  358,  362, 

364 
supply,    high    elevation,    long 

distance  control 294 

tank,  expansion 32 

expansion  air  type 276 


PAGE 

Water  tank  (continued). 

float  valve,  pilot  control 276 

gravity .32,  272 

in  building,  precaution  against 

sweating  and  leakage. .  .      273 

in  smoke  flue 390 

Water-hammer,  blow-off  lines. ...       68 

economizer 69,  454 

suction  lines 250 

Water  ways,  access  wells 297 

arranged  for  cleaning 298 

at  high  bluff 306,  315,  316 

deep  in  ground 317 

faulty  design 303 

foundation 302 

gravity  flow 295,  313 

in  rock 297 

intake  and  discharge  alongside 

each  other 321 

for  cooling  pond 304 

ice  thawing 299,  313 

large  valve 301 

of  brick 298 

of  formed  concrete 298,  299 

of  wood 296 

part  of  building  foundation.  . .  .     321 

screen  house,  anchorage 303 

steel  pipe 297 

through  made  ground 296 

used    as   either    intake    of  dis- 
charge        42 

mouth  of  intake,  299,  300,  303,  304, 

306,  313,  3iS,  3*6 

Whistles,  air  operated 410 

condensation  discharge .     139 


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